Bug Summary

File:llvm/include/llvm/ADT/APInt.h
Warning:line 927, column 15
Assigned value is garbage or undefined

Annotated Source Code

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clang -cc1 -cc1 -triple x86_64-pc-linux-gnu -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name BasicAliasAnalysis.cpp -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=cplusplus -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -analyzer-config-compatibility-mode=true -mrelocation-model pic -pic-level 2 -mframe-pointer=none -fmath-errno -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -tune-cpu generic -fno-split-dwarf-inlining -debugger-tuning=gdb -ffunction-sections -fdata-sections -resource-dir /usr/lib/llvm-12/lib/clang/12.0.0 -D _DEBUG -D _GNU_SOURCE -D __STDC_CONSTANT_MACROS -D __STDC_FORMAT_MACROS -D __STDC_LIMIT_MACROS -I /build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/build-llvm/lib/Analysis -I /build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis -I /build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/build-llvm/include -I /build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include -U NDEBUG -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/x86_64-linux-gnu/c++/6.3.0 -internal-isystem /usr/lib/gcc/x86_64-linux-gnu/6.3.0/../../../../include/c++/6.3.0/backward -internal-isystem /usr/local/include -internal-isystem /usr/lib/llvm-12/lib/clang/12.0.0/include -internal-externc-isystem /usr/include/x86_64-linux-gnu -internal-externc-isystem /include -internal-externc-isystem /usr/include -O2 -Wno-unused-parameter -Wwrite-strings -Wno-missing-field-initializers -Wno-long-long -Wno-maybe-uninitialized -Wno-comment -std=c++14 -fdeprecated-macro -fdebug-compilation-dir /build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/build-llvm/lib/Analysis -fdebug-prefix-map=/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb=. -ferror-limit 19 -fvisibility-inlines-hidden -stack-protector 2 -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -analyzer-output=html -analyzer-config stable-report-filename=true -faddrsig -o /tmp/scan-build-2020-09-26-161721-17566-1 -x c++ /build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp

/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp

1//===- BasicAliasAnalysis.cpp - Stateless Alias Analysis Impl -------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file defines the primary stateless implementation of the
10// Alias Analysis interface that implements identities (two different
11// globals cannot alias, etc), but does no stateful analysis.
12//
13//===----------------------------------------------------------------------===//
14
15#include "llvm/Analysis/BasicAliasAnalysis.h"
16#include "llvm/ADT/APInt.h"
17#include "llvm/ADT/SmallPtrSet.h"
18#include "llvm/ADT/SmallVector.h"
19#include "llvm/ADT/Statistic.h"
20#include "llvm/Analysis/AliasAnalysis.h"
21#include "llvm/Analysis/AssumptionCache.h"
22#include "llvm/Analysis/CFG.h"
23#include "llvm/Analysis/CaptureTracking.h"
24#include "llvm/Analysis/InstructionSimplify.h"
25#include "llvm/Analysis/LoopInfo.h"
26#include "llvm/Analysis/MemoryBuiltins.h"
27#include "llvm/Analysis/MemoryLocation.h"
28#include "llvm/Analysis/PhiValues.h"
29#include "llvm/Analysis/TargetLibraryInfo.h"
30#include "llvm/Analysis/ValueTracking.h"
31#include "llvm/IR/Argument.h"
32#include "llvm/IR/Attributes.h"
33#include "llvm/IR/Constant.h"
34#include "llvm/IR/Constants.h"
35#include "llvm/IR/DataLayout.h"
36#include "llvm/IR/DerivedTypes.h"
37#include "llvm/IR/Dominators.h"
38#include "llvm/IR/Function.h"
39#include "llvm/IR/GetElementPtrTypeIterator.h"
40#include "llvm/IR/GlobalAlias.h"
41#include "llvm/IR/GlobalVariable.h"
42#include "llvm/IR/InstrTypes.h"
43#include "llvm/IR/Instruction.h"
44#include "llvm/IR/Instructions.h"
45#include "llvm/IR/IntrinsicInst.h"
46#include "llvm/IR/Intrinsics.h"
47#include "llvm/IR/Metadata.h"
48#include "llvm/IR/Operator.h"
49#include "llvm/IR/Type.h"
50#include "llvm/IR/User.h"
51#include "llvm/IR/Value.h"
52#include "llvm/InitializePasses.h"
53#include "llvm/Pass.h"
54#include "llvm/Support/Casting.h"
55#include "llvm/Support/CommandLine.h"
56#include "llvm/Support/Compiler.h"
57#include "llvm/Support/KnownBits.h"
58#include <cassert>
59#include <cstdint>
60#include <cstdlib>
61#include <utility>
62
63#define DEBUG_TYPE"basicaa" "basicaa"
64
65using namespace llvm;
66
67/// Enable analysis of recursive PHI nodes.
68static cl::opt<bool> EnableRecPhiAnalysis("basic-aa-recphi", cl::Hidden,
69 cl::init(true));
70
71/// By default, even on 32-bit architectures we use 64-bit integers for
72/// calculations. This will allow us to more-aggressively decompose indexing
73/// expressions calculated using i64 values (e.g., long long in C) which is
74/// common enough to worry about.
75static cl::opt<bool> ForceAtLeast64Bits("basic-aa-force-at-least-64b",
76 cl::Hidden, cl::init(true));
77static cl::opt<bool> DoubleCalcBits("basic-aa-double-calc-bits",
78 cl::Hidden, cl::init(false));
79
80/// SearchLimitReached / SearchTimes shows how often the limit of
81/// to decompose GEPs is reached. It will affect the precision
82/// of basic alias analysis.
83STATISTIC(SearchLimitReached, "Number of times the limit to "static llvm::Statistic SearchLimitReached = {"basicaa", "SearchLimitReached"
, "Number of times the limit to " "decompose GEPs is reached"
}
84 "decompose GEPs is reached")static llvm::Statistic SearchLimitReached = {"basicaa", "SearchLimitReached"
, "Number of times the limit to " "decompose GEPs is reached"
}
;
85STATISTIC(SearchTimes, "Number of times a GEP is decomposed")static llvm::Statistic SearchTimes = {"basicaa", "SearchTimes"
, "Number of times a GEP is decomposed"}
;
86
87/// Cutoff after which to stop analysing a set of phi nodes potentially involved
88/// in a cycle. Because we are analysing 'through' phi nodes, we need to be
89/// careful with value equivalence. We use reachability to make sure a value
90/// cannot be involved in a cycle.
91const unsigned MaxNumPhiBBsValueReachabilityCheck = 20;
92
93// The max limit of the search depth in DecomposeGEPExpression() and
94// getUnderlyingObject(), both functions need to use the same search
95// depth otherwise the algorithm in aliasGEP will assert.
96static const unsigned MaxLookupSearchDepth = 6;
97
98bool BasicAAResult::invalidate(Function &Fn, const PreservedAnalyses &PA,
99 FunctionAnalysisManager::Invalidator &Inv) {
100 // We don't care if this analysis itself is preserved, it has no state. But
101 // we need to check that the analyses it depends on have been. Note that we
102 // may be created without handles to some analyses and in that case don't
103 // depend on them.
104 if (Inv.invalidate<AssumptionAnalysis>(Fn, PA) ||
105 (DT && Inv.invalidate<DominatorTreeAnalysis>(Fn, PA)) ||
106 (LI && Inv.invalidate<LoopAnalysis>(Fn, PA)) ||
107 (PV && Inv.invalidate<PhiValuesAnalysis>(Fn, PA)))
108 return true;
109
110 // Otherwise this analysis result remains valid.
111 return false;
112}
113
114//===----------------------------------------------------------------------===//
115// Useful predicates
116//===----------------------------------------------------------------------===//
117
118/// Returns true if the pointer is to a function-local object that never
119/// escapes from the function.
120static bool isNonEscapingLocalObject(
121 const Value *V,
122 SmallDenseMap<const Value *, bool, 8> *IsCapturedCache = nullptr) {
123 SmallDenseMap<const Value *, bool, 8>::iterator CacheIt;
124 if (IsCapturedCache) {
125 bool Inserted;
126 std::tie(CacheIt, Inserted) = IsCapturedCache->insert({V, false});
127 if (!Inserted)
128 // Found cached result, return it!
129 return CacheIt->second;
130 }
131
132 // If this is a local allocation, check to see if it escapes.
133 if (isa<AllocaInst>(V) || isNoAliasCall(V)) {
134 // Set StoreCaptures to True so that we can assume in our callers that the
135 // pointer is not the result of a load instruction. Currently
136 // PointerMayBeCaptured doesn't have any special analysis for the
137 // StoreCaptures=false case; if it did, our callers could be refined to be
138 // more precise.
139 auto Ret = !PointerMayBeCaptured(V, false, /*StoreCaptures=*/true);
140 if (IsCapturedCache)
141 CacheIt->second = Ret;
142 return Ret;
143 }
144
145 // If this is an argument that corresponds to a byval or noalias argument,
146 // then it has not escaped before entering the function. Check if it escapes
147 // inside the function.
148 if (const Argument *A = dyn_cast<Argument>(V))
149 if (A->hasByValAttr() || A->hasNoAliasAttr()) {
150 // Note even if the argument is marked nocapture, we still need to check
151 // for copies made inside the function. The nocapture attribute only
152 // specifies that there are no copies made that outlive the function.
153 auto Ret = !PointerMayBeCaptured(V, false, /*StoreCaptures=*/true);
154 if (IsCapturedCache)
155 CacheIt->second = Ret;
156 return Ret;
157 }
158
159 return false;
160}
161
162/// Returns true if the pointer is one which would have been considered an
163/// escape by isNonEscapingLocalObject.
164static bool isEscapeSource(const Value *V) {
165 if (isa<CallBase>(V))
166 return true;
167
168 if (isa<Argument>(V))
169 return true;
170
171 // The load case works because isNonEscapingLocalObject considers all
172 // stores to be escapes (it passes true for the StoreCaptures argument
173 // to PointerMayBeCaptured).
174 if (isa<LoadInst>(V))
175 return true;
176
177 return false;
178}
179
180/// Returns the size of the object specified by V or UnknownSize if unknown.
181static uint64_t getObjectSize(const Value *V, const DataLayout &DL,
182 const TargetLibraryInfo &TLI,
183 bool NullIsValidLoc,
184 bool RoundToAlign = false) {
185 uint64_t Size;
186 ObjectSizeOpts Opts;
187 Opts.RoundToAlign = RoundToAlign;
188 Opts.NullIsUnknownSize = NullIsValidLoc;
189 if (getObjectSize(V, Size, DL, &TLI, Opts))
190 return Size;
191 return MemoryLocation::UnknownSize;
192}
193
194/// Returns true if we can prove that the object specified by V is smaller than
195/// Size.
196static bool isObjectSmallerThan(const Value *V, uint64_t Size,
197 const DataLayout &DL,
198 const TargetLibraryInfo &TLI,
199 bool NullIsValidLoc) {
200 // Note that the meanings of the "object" are slightly different in the
201 // following contexts:
202 // c1: llvm::getObjectSize()
203 // c2: llvm.objectsize() intrinsic
204 // c3: isObjectSmallerThan()
205 // c1 and c2 share the same meaning; however, the meaning of "object" in c3
206 // refers to the "entire object".
207 //
208 // Consider this example:
209 // char *p = (char*)malloc(100)
210 // char *q = p+80;
211 //
212 // In the context of c1 and c2, the "object" pointed by q refers to the
213 // stretch of memory of q[0:19]. So, getObjectSize(q) should return 20.
214 //
215 // However, in the context of c3, the "object" refers to the chunk of memory
216 // being allocated. So, the "object" has 100 bytes, and q points to the middle
217 // the "object". In case q is passed to isObjectSmallerThan() as the 1st
218 // parameter, before the llvm::getObjectSize() is called to get the size of
219 // entire object, we should:
220 // - either rewind the pointer q to the base-address of the object in
221 // question (in this case rewind to p), or
222 // - just give up. It is up to caller to make sure the pointer is pointing
223 // to the base address the object.
224 //
225 // We go for 2nd option for simplicity.
226 if (!isIdentifiedObject(V))
227 return false;
228
229 // This function needs to use the aligned object size because we allow
230 // reads a bit past the end given sufficient alignment.
231 uint64_t ObjectSize = getObjectSize(V, DL, TLI, NullIsValidLoc,
232 /*RoundToAlign*/ true);
233
234 return ObjectSize != MemoryLocation::UnknownSize && ObjectSize < Size;
235}
236
237/// Return the minimal extent from \p V to the end of the underlying object,
238/// assuming the result is used in an aliasing query. E.g., we do use the query
239/// location size and the fact that null pointers cannot alias here.
240static uint64_t getMinimalExtentFrom(const Value &V,
241 const LocationSize &LocSize,
242 const DataLayout &DL,
243 bool NullIsValidLoc) {
244 // If we have dereferenceability information we know a lower bound for the
245 // extent as accesses for a lower offset would be valid. We need to exclude
246 // the "or null" part if null is a valid pointer.
247 bool CanBeNull;
248 uint64_t DerefBytes = V.getPointerDereferenceableBytes(DL, CanBeNull);
249 DerefBytes = (CanBeNull && NullIsValidLoc) ? 0 : DerefBytes;
250 // If queried with a precise location size, we assume that location size to be
251 // accessed, thus valid.
252 if (LocSize.isPrecise())
253 DerefBytes = std::max(DerefBytes, LocSize.getValue());
254 return DerefBytes;
255}
256
257/// Returns true if we can prove that the object specified by V has size Size.
258static bool isObjectSize(const Value *V, uint64_t Size, const DataLayout &DL,
259 const TargetLibraryInfo &TLI, bool NullIsValidLoc) {
260 uint64_t ObjectSize = getObjectSize(V, DL, TLI, NullIsValidLoc);
261 return ObjectSize != MemoryLocation::UnknownSize && ObjectSize == Size;
262}
263
264//===----------------------------------------------------------------------===//
265// GetElementPtr Instruction Decomposition and Analysis
266//===----------------------------------------------------------------------===//
267
268/// Analyzes the specified value as a linear expression: "A*V + B", where A and
269/// B are constant integers.
270///
271/// Returns the scale and offset values as APInts and return V as a Value*, and
272/// return whether we looked through any sign or zero extends. The incoming
273/// Value is known to have IntegerType, and it may already be sign or zero
274/// extended.
275///
276/// Note that this looks through extends, so the high bits may not be
277/// represented in the result.
278/*static*/ const Value *BasicAAResult::GetLinearExpression(
279 const Value *V, APInt &Scale, APInt &Offset, unsigned &ZExtBits,
280 unsigned &SExtBits, const DataLayout &DL, unsigned Depth,
281 AssumptionCache *AC, DominatorTree *DT, bool &NSW, bool &NUW) {
282 assert(V->getType()->isIntegerTy() && "Not an integer value")((V->getType()->isIntegerTy() && "Not an integer value"
) ? static_cast<void> (0) : __assert_fail ("V->getType()->isIntegerTy() && \"Not an integer value\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 282, __PRETTY_FUNCTION__))
;
7
'?' condition is true
283
284 // Limit our recursion depth.
285 if (Depth
7.1
'Depth' is not equal to 6
7.1
'Depth' is not equal to 6
== 6) {
8
Taking false branch
286 Scale = 1;
287 Offset = 0;
288 return V;
289 }
290
291 if (const ConstantInt *Const
9.1
'Const' is null
9.1
'Const' is null
= dyn_cast<ConstantInt>(V)) {
9
Assuming 'V' is not a 'ConstantInt'
10
Taking false branch
292 // If it's a constant, just convert it to an offset and remove the variable.
293 // If we've been called recursively, the Offset bit width will be greater
294 // than the constant's (the Offset's always as wide as the outermost call),
295 // so we'll zext here and process any extension in the isa<SExtInst> &
296 // isa<ZExtInst> cases below.
297 Offset += Const->getValue().zextOrSelf(Offset.getBitWidth());
298 assert(Scale == 0 && "Constant values don't have a scale")((Scale == 0 && "Constant values don't have a scale")
? static_cast<void> (0) : __assert_fail ("Scale == 0 && \"Constant values don't have a scale\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 298, __PRETTY_FUNCTION__))
;
299 return V;
300 }
301
302 if (const BinaryOperator *BOp
11.1
'BOp' is non-null
11.1
'BOp' is non-null
= dyn_cast<BinaryOperator>(V)) {
11
Assuming 'V' is a 'BinaryOperator'
12
Taking true branch
303 if (ConstantInt *RHSC = dyn_cast<ConstantInt>(BOp->getOperand(1))) {
13
Assuming 'RHSC' is non-null
14
Taking true branch
304 // If we've been called recursively, then Offset and Scale will be wider
305 // than the BOp operands. We'll always zext it here as we'll process sign
306 // extensions below (see the isa<SExtInst> / isa<ZExtInst> cases).
307 APInt RHS = RHSC->getValue().zextOrSelf(Offset.getBitWidth());
308
309 switch (BOp->getOpcode()) {
15
Control jumps to 'case Shl:' at line 342
310 default:
311 // We don't understand this instruction, so we can't decompose it any
312 // further.
313 Scale = 1;
314 Offset = 0;
315 return V;
316 case Instruction::Or:
317 // X|C == X+C if all the bits in C are unset in X. Otherwise we can't
318 // analyze it.
319 if (!MaskedValueIsZero(BOp->getOperand(0), RHSC->getValue(), DL, 0, AC,
320 BOp, DT)) {
321 Scale = 1;
322 Offset = 0;
323 return V;
324 }
325 LLVM_FALLTHROUGH[[gnu::fallthrough]];
326 case Instruction::Add:
327 V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, ZExtBits,
328 SExtBits, DL, Depth + 1, AC, DT, NSW, NUW);
329 Offset += RHS;
330 break;
331 case Instruction::Sub:
332 V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, ZExtBits,
333 SExtBits, DL, Depth + 1, AC, DT, NSW, NUW);
334 Offset -= RHS;
335 break;
336 case Instruction::Mul:
337 V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, ZExtBits,
338 SExtBits, DL, Depth + 1, AC, DT, NSW, NUW);
339 Offset *= RHS;
340 Scale *= RHS;
341 break;
342 case Instruction::Shl:
343 V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, ZExtBits,
344 SExtBits, DL, Depth + 1, AC, DT, NSW, NUW);
345
346 // We're trying to linearize an expression of the kind:
347 // shl i8 -128, 36
348 // where the shift count exceeds the bitwidth of the type.
349 // We can't decompose this further (the expression would return
350 // a poison value).
351 if (Offset.getBitWidth() < RHS.getLimitedValue() ||
16
Assuming the condition is false
18
Taking false branch
352 Scale.getBitWidth() < RHS.getLimitedValue()) {
17
Assuming the condition is false
353 Scale = 1;
354 Offset = 0;
355 return V;
356 }
357
358 Offset <<= RHS.getLimitedValue();
19
Passing the value 18446744073709551615 via 1st parameter 'Limit'
20
Calling 'APInt::getLimitedValue'
23
Returning from 'APInt::getLimitedValue'
24
Passing the value 4294967295 via 1st parameter 'ShiftAmt'
25
Calling 'APInt::operator<<='
359 Scale <<= RHS.getLimitedValue();
360 // the semantics of nsw and nuw for left shifts don't match those of
361 // multiplications, so we won't propagate them.
362 NSW = NUW = false;
363 return V;
364 }
365
366 if (isa<OverflowingBinaryOperator>(BOp)) {
367 NUW &= BOp->hasNoUnsignedWrap();
368 NSW &= BOp->hasNoSignedWrap();
369 }
370 return V;
371 }
372 }
373
374 // Since GEP indices are sign extended anyway, we don't care about the high
375 // bits of a sign or zero extended value - just scales and offsets. The
376 // extensions have to be consistent though.
377 if (isa<SExtInst>(V) || isa<ZExtInst>(V)) {
378 Value *CastOp = cast<CastInst>(V)->getOperand(0);
379 unsigned NewWidth = V->getType()->getPrimitiveSizeInBits();
380 unsigned SmallWidth = CastOp->getType()->getPrimitiveSizeInBits();
381 unsigned OldZExtBits = ZExtBits, OldSExtBits = SExtBits;
382 const Value *Result =
383 GetLinearExpression(CastOp, Scale, Offset, ZExtBits, SExtBits, DL,
384 Depth + 1, AC, DT, NSW, NUW);
385
386 // zext(zext(%x)) == zext(%x), and similarly for sext; we'll handle this
387 // by just incrementing the number of bits we've extended by.
388 unsigned ExtendedBy = NewWidth - SmallWidth;
389
390 if (isa<SExtInst>(V) && ZExtBits == 0) {
391 // sext(sext(%x, a), b) == sext(%x, a + b)
392
393 if (NSW) {
394 // We haven't sign-wrapped, so it's valid to decompose sext(%x + c)
395 // into sext(%x) + sext(c). We'll sext the Offset ourselves:
396 unsigned OldWidth = Offset.getBitWidth();
397 Offset = Offset.trunc(SmallWidth).sext(NewWidth).zextOrSelf(OldWidth);
398 } else {
399 // We may have signed-wrapped, so don't decompose sext(%x + c) into
400 // sext(%x) + sext(c)
401 Scale = 1;
402 Offset = 0;
403 Result = CastOp;
404 ZExtBits = OldZExtBits;
405 SExtBits = OldSExtBits;
406 }
407 SExtBits += ExtendedBy;
408 } else {
409 // sext(zext(%x, a), b) = zext(zext(%x, a), b) = zext(%x, a + b)
410
411 if (!NUW) {
412 // We may have unsigned-wrapped, so don't decompose zext(%x + c) into
413 // zext(%x) + zext(c)
414 Scale = 1;
415 Offset = 0;
416 Result = CastOp;
417 ZExtBits = OldZExtBits;
418 SExtBits = OldSExtBits;
419 }
420 ZExtBits += ExtendedBy;
421 }
422
423 return Result;
424 }
425
426 Scale = 1;
427 Offset = 0;
428 return V;
429}
430
431/// To ensure a pointer offset fits in an integer of size PointerSize
432/// (in bits) when that size is smaller than the maximum pointer size. This is
433/// an issue, for example, in particular for 32b pointers with negative indices
434/// that rely on two's complement wrap-arounds for precise alias information
435/// where the maximum pointer size is 64b.
436static APInt adjustToPointerSize(const APInt &Offset, unsigned PointerSize) {
437 assert(PointerSize <= Offset.getBitWidth() && "Invalid PointerSize!")((PointerSize <= Offset.getBitWidth() && "Invalid PointerSize!"
) ? static_cast<void> (0) : __assert_fail ("PointerSize <= Offset.getBitWidth() && \"Invalid PointerSize!\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 437, __PRETTY_FUNCTION__))
;
438 unsigned ShiftBits = Offset.getBitWidth() - PointerSize;
439 return (Offset << ShiftBits).ashr(ShiftBits);
440}
441
442static unsigned getMaxPointerSize(const DataLayout &DL) {
443 unsigned MaxPointerSize = DL.getMaxPointerSizeInBits();
444 if (MaxPointerSize < 64 && ForceAtLeast64Bits) MaxPointerSize = 64;
445 if (DoubleCalcBits) MaxPointerSize *= 2;
446
447 return MaxPointerSize;
448}
449
450/// If V is a symbolic pointer expression, decompose it into a base pointer
451/// with a constant offset and a number of scaled symbolic offsets.
452///
453/// The scaled symbolic offsets (represented by pairs of a Value* and a scale
454/// in the VarIndices vector) are Value*'s that are known to be scaled by the
455/// specified amount, but which may have other unrepresented high bits. As
456/// such, the gep cannot necessarily be reconstructed from its decomposed form.
457///
458/// When DataLayout is around, this function is capable of analyzing everything
459/// that getUnderlyingObject can look through. To be able to do that
460/// getUnderlyingObject and DecomposeGEPExpression must use the same search
461/// depth (MaxLookupSearchDepth). When DataLayout not is around, it just looks
462/// through pointer casts.
463bool BasicAAResult::DecomposeGEPExpression(const Value *V,
464 DecomposedGEP &Decomposed, const DataLayout &DL, AssumptionCache *AC,
465 DominatorTree *DT) {
466 // Limit recursion depth to limit compile time in crazy cases.
467 unsigned MaxLookup = MaxLookupSearchDepth;
468 SearchTimes++;
469
470 unsigned MaxPointerSize = getMaxPointerSize(DL);
471 Decomposed.VarIndices.clear();
472 do {
473 // See if this is a bitcast or GEP.
474 const Operator *Op = dyn_cast<Operator>(V);
475 if (!Op) {
476 // The only non-operator case we can handle are GlobalAliases.
477 if (const GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
478 if (!GA->isInterposable()) {
479 V = GA->getAliasee();
480 continue;
481 }
482 }
483 Decomposed.Base = V;
484 return false;
485 }
486
487 if (Op->getOpcode() == Instruction::BitCast ||
488 Op->getOpcode() == Instruction::AddrSpaceCast) {
489 V = Op->getOperand(0);
490 continue;
491 }
492
493 const GEPOperator *GEPOp = dyn_cast<GEPOperator>(Op);
494 if (!GEPOp) {
495 if (const auto *PHI = dyn_cast<PHINode>(V)) {
496 // Look through single-arg phi nodes created by LCSSA.
497 if (PHI->getNumIncomingValues() == 1) {
498 V = PHI->getIncomingValue(0);
499 continue;
500 }
501 } else if (const auto *Call = dyn_cast<CallBase>(V)) {
502 // CaptureTracking can know about special capturing properties of some
503 // intrinsics like launder.invariant.group, that can't be expressed with
504 // the attributes, but have properties like returning aliasing pointer.
505 // Because some analysis may assume that nocaptured pointer is not
506 // returned from some special intrinsic (because function would have to
507 // be marked with returns attribute), it is crucial to use this function
508 // because it should be in sync with CaptureTracking. Not using it may
509 // cause weird miscompilations where 2 aliasing pointers are assumed to
510 // noalias.
511 if (auto *RP = getArgumentAliasingToReturnedPointer(Call, false)) {
512 V = RP;
513 continue;
514 }
515 }
516
517 Decomposed.Base = V;
518 return false;
519 }
520
521 // Don't attempt to analyze GEPs over unsized objects.
522 if (!GEPOp->getSourceElementType()->isSized()) {
523 Decomposed.Base = V;
524 return false;
525 }
526
527 // Don't attempt to analyze GEPs if index scale is not a compile-time
528 // constant.
529 if (isa<ScalableVectorType>(GEPOp->getSourceElementType())) {
530 Decomposed.Base = V;
531 Decomposed.HasCompileTimeConstantScale = false;
532 return false;
533 }
534
535 unsigned AS = GEPOp->getPointerAddressSpace();
536 // Walk the indices of the GEP, accumulating them into BaseOff/VarIndices.
537 gep_type_iterator GTI = gep_type_begin(GEPOp);
538 unsigned PointerSize = DL.getPointerSizeInBits(AS);
539 // Assume all GEP operands are constants until proven otherwise.
540 bool GepHasConstantOffset = true;
541 for (User::const_op_iterator I = GEPOp->op_begin() + 1, E = GEPOp->op_end();
542 I != E; ++I, ++GTI) {
543 const Value *Index = *I;
544 // Compute the (potentially symbolic) offset in bytes for this index.
545 if (StructType *STy = GTI.getStructTypeOrNull()) {
546 // For a struct, add the member offset.
547 unsigned FieldNo = cast<ConstantInt>(Index)->getZExtValue();
548 if (FieldNo == 0)
549 continue;
550
551 Decomposed.StructOffset +=
552 DL.getStructLayout(STy)->getElementOffset(FieldNo);
553 continue;
554 }
555
556 // For an array/pointer, add the element offset, explicitly scaled.
557 if (const ConstantInt *CIdx = dyn_cast<ConstantInt>(Index)) {
558 if (CIdx->isZero())
559 continue;
560 Decomposed.OtherOffset +=
561 (DL.getTypeAllocSize(GTI.getIndexedType()).getFixedSize() *
562 CIdx->getValue().sextOrSelf(MaxPointerSize))
563 .sextOrTrunc(MaxPointerSize);
564 continue;
565 }
566
567 GepHasConstantOffset = false;
568
569 APInt Scale(MaxPointerSize,
570 DL.getTypeAllocSize(GTI.getIndexedType()).getFixedSize());
571 unsigned ZExtBits = 0, SExtBits = 0;
572
573 // If the integer type is smaller than the pointer size, it is implicitly
574 // sign extended to pointer size.
575 unsigned Width = Index->getType()->getIntegerBitWidth();
576 if (PointerSize > Width)
577 SExtBits += PointerSize - Width;
578
579 // Use GetLinearExpression to decompose the index into a C1*V+C2 form.
580 APInt IndexScale(Width, 0), IndexOffset(Width, 0);
581 bool NSW = true, NUW = true;
582 const Value *OrigIndex = Index;
583 Index = GetLinearExpression(Index, IndexScale, IndexOffset, ZExtBits,
584 SExtBits, DL, 0, AC, DT, NSW, NUW);
585
586 // The GEP index scale ("Scale") scales C1*V+C2, yielding (C1*V+C2)*Scale.
587 // This gives us an aggregate computation of (C1*Scale)*V + C2*Scale.
588
589 // It can be the case that, even through C1*V+C2 does not overflow for
590 // relevant values of V, (C2*Scale) can overflow. In that case, we cannot
591 // decompose the expression in this way.
592 //
593 // FIXME: C1*Scale and the other operations in the decomposed
594 // (C1*Scale)*V+C2*Scale can also overflow. We should check for this
595 // possibility.
596 APInt WideScaledOffset = IndexOffset.sextOrTrunc(MaxPointerSize*2) *
597 Scale.sext(MaxPointerSize*2);
598 if (WideScaledOffset.getMinSignedBits() > MaxPointerSize) {
599 Index = OrigIndex;
600 IndexScale = 1;
601 IndexOffset = 0;
602
603 ZExtBits = SExtBits = 0;
604 if (PointerSize > Width)
605 SExtBits += PointerSize - Width;
606 } else {
607 Decomposed.OtherOffset += IndexOffset.sextOrTrunc(MaxPointerSize) * Scale;
608 Scale *= IndexScale.sextOrTrunc(MaxPointerSize);
609 }
610
611 // If we already had an occurrence of this index variable, merge this
612 // scale into it. For example, we want to handle:
613 // A[x][x] -> x*16 + x*4 -> x*20
614 // This also ensures that 'x' only appears in the index list once.
615 for (unsigned i = 0, e = Decomposed.VarIndices.size(); i != e; ++i) {
616 if (Decomposed.VarIndices[i].V == Index &&
617 Decomposed.VarIndices[i].ZExtBits == ZExtBits &&
618 Decomposed.VarIndices[i].SExtBits == SExtBits) {
619 Scale += Decomposed.VarIndices[i].Scale;
620 Decomposed.VarIndices.erase(Decomposed.VarIndices.begin() + i);
621 break;
622 }
623 }
624
625 // Make sure that we have a scale that makes sense for this target's
626 // pointer size.
627 Scale = adjustToPointerSize(Scale, PointerSize);
628
629 if (!!Scale) {
630 VariableGEPIndex Entry = {Index, ZExtBits, SExtBits, Scale};
631 Decomposed.VarIndices.push_back(Entry);
632 }
633 }
634
635 // Take care of wrap-arounds
636 if (GepHasConstantOffset) {
637 Decomposed.StructOffset =
638 adjustToPointerSize(Decomposed.StructOffset, PointerSize);
639 Decomposed.OtherOffset =
640 adjustToPointerSize(Decomposed.OtherOffset, PointerSize);
641 }
642
643 // Analyze the base pointer next.
644 V = GEPOp->getOperand(0);
645 } while (--MaxLookup);
646
647 // If the chain of expressions is too deep, just return early.
648 Decomposed.Base = V;
649 SearchLimitReached++;
650 return true;
651}
652
653/// Returns whether the given pointer value points to memory that is local to
654/// the function, with global constants being considered local to all
655/// functions.
656bool BasicAAResult::pointsToConstantMemory(const MemoryLocation &Loc,
657 AAQueryInfo &AAQI, bool OrLocal) {
658 assert(Visited.empty() && "Visited must be cleared after use!")((Visited.empty() && "Visited must be cleared after use!"
) ? static_cast<void> (0) : __assert_fail ("Visited.empty() && \"Visited must be cleared after use!\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 658, __PRETTY_FUNCTION__))
;
659
660 unsigned MaxLookup = 8;
661 SmallVector<const Value *, 16> Worklist;
662 Worklist.push_back(Loc.Ptr);
663 do {
664 const Value *V = getUnderlyingObject(Worklist.pop_back_val());
665 if (!Visited.insert(V).second) {
666 Visited.clear();
667 return AAResultBase::pointsToConstantMemory(Loc, AAQI, OrLocal);
668 }
669
670 // An alloca instruction defines local memory.
671 if (OrLocal && isa<AllocaInst>(V))
672 continue;
673
674 // A global constant counts as local memory for our purposes.
675 if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(V)) {
676 // Note: this doesn't require GV to be "ODR" because it isn't legal for a
677 // global to be marked constant in some modules and non-constant in
678 // others. GV may even be a declaration, not a definition.
679 if (!GV->isConstant()) {
680 Visited.clear();
681 return AAResultBase::pointsToConstantMemory(Loc, AAQI, OrLocal);
682 }
683 continue;
684 }
685
686 // If both select values point to local memory, then so does the select.
687 if (const SelectInst *SI = dyn_cast<SelectInst>(V)) {
688 Worklist.push_back(SI->getTrueValue());
689 Worklist.push_back(SI->getFalseValue());
690 continue;
691 }
692
693 // If all values incoming to a phi node point to local memory, then so does
694 // the phi.
695 if (const PHINode *PN = dyn_cast<PHINode>(V)) {
696 // Don't bother inspecting phi nodes with many operands.
697 if (PN->getNumIncomingValues() > MaxLookup) {
698 Visited.clear();
699 return AAResultBase::pointsToConstantMemory(Loc, AAQI, OrLocal);
700 }
701 for (Value *IncValue : PN->incoming_values())
702 Worklist.push_back(IncValue);
703 continue;
704 }
705
706 // Otherwise be conservative.
707 Visited.clear();
708 return AAResultBase::pointsToConstantMemory(Loc, AAQI, OrLocal);
709 } while (!Worklist.empty() && --MaxLookup);
710
711 Visited.clear();
712 return Worklist.empty();
713}
714
715/// Returns the behavior when calling the given call site.
716FunctionModRefBehavior BasicAAResult::getModRefBehavior(const CallBase *Call) {
717 if (Call->doesNotAccessMemory())
718 // Can't do better than this.
719 return FMRB_DoesNotAccessMemory;
720
721 FunctionModRefBehavior Min = FMRB_UnknownModRefBehavior;
722
723 // If the callsite knows it only reads memory, don't return worse
724 // than that.
725 if (Call->onlyReadsMemory())
726 Min = FMRB_OnlyReadsMemory;
727 else if (Call->doesNotReadMemory())
728 Min = FMRB_OnlyWritesMemory;
729
730 if (Call->onlyAccessesArgMemory())
731 Min = FunctionModRefBehavior(Min & FMRB_OnlyAccessesArgumentPointees);
732 else if (Call->onlyAccessesInaccessibleMemory())
733 Min = FunctionModRefBehavior(Min & FMRB_OnlyAccessesInaccessibleMem);
734 else if (Call->onlyAccessesInaccessibleMemOrArgMem())
735 Min = FunctionModRefBehavior(Min & FMRB_OnlyAccessesInaccessibleOrArgMem);
736
737 // If the call has operand bundles then aliasing attributes from the function
738 // it calls do not directly apply to the call. This can be made more precise
739 // in the future.
740 if (!Call->hasOperandBundles())
741 if (const Function *F = Call->getCalledFunction())
742 Min =
743 FunctionModRefBehavior(Min & getBestAAResults().getModRefBehavior(F));
744
745 return Min;
746}
747
748/// Returns the behavior when calling the given function. For use when the call
749/// site is not known.
750FunctionModRefBehavior BasicAAResult::getModRefBehavior(const Function *F) {
751 // If the function declares it doesn't access memory, we can't do better.
752 if (F->doesNotAccessMemory())
753 return FMRB_DoesNotAccessMemory;
754
755 FunctionModRefBehavior Min = FMRB_UnknownModRefBehavior;
756
757 // If the function declares it only reads memory, go with that.
758 if (F->onlyReadsMemory())
759 Min = FMRB_OnlyReadsMemory;
760 else if (F->doesNotReadMemory())
761 Min = FMRB_OnlyWritesMemory;
762
763 if (F->onlyAccessesArgMemory())
764 Min = FunctionModRefBehavior(Min & FMRB_OnlyAccessesArgumentPointees);
765 else if (F->onlyAccessesInaccessibleMemory())
766 Min = FunctionModRefBehavior(Min & FMRB_OnlyAccessesInaccessibleMem);
767 else if (F->onlyAccessesInaccessibleMemOrArgMem())
768 Min = FunctionModRefBehavior(Min & FMRB_OnlyAccessesInaccessibleOrArgMem);
769
770 return Min;
771}
772
773/// Returns true if this is a writeonly (i.e Mod only) parameter.
774static bool isWriteOnlyParam(const CallBase *Call, unsigned ArgIdx,
775 const TargetLibraryInfo &TLI) {
776 if (Call->paramHasAttr(ArgIdx, Attribute::WriteOnly))
777 return true;
778
779 // We can bound the aliasing properties of memset_pattern16 just as we can
780 // for memcpy/memset. This is particularly important because the
781 // LoopIdiomRecognizer likes to turn loops into calls to memset_pattern16
782 // whenever possible.
783 // FIXME Consider handling this in InferFunctionAttr.cpp together with other
784 // attributes.
785 LibFunc F;
786 if (Call->getCalledFunction() &&
787 TLI.getLibFunc(*Call->getCalledFunction(), F) &&
788 F == LibFunc_memset_pattern16 && TLI.has(F))
789 if (ArgIdx == 0)
790 return true;
791
792 // TODO: memset_pattern4, memset_pattern8
793 // TODO: _chk variants
794 // TODO: strcmp, strcpy
795
796 return false;
797}
798
799ModRefInfo BasicAAResult::getArgModRefInfo(const CallBase *Call,
800 unsigned ArgIdx) {
801 // Checking for known builtin intrinsics and target library functions.
802 if (isWriteOnlyParam(Call, ArgIdx, TLI))
803 return ModRefInfo::Mod;
804
805 if (Call->paramHasAttr(ArgIdx, Attribute::ReadOnly))
806 return ModRefInfo::Ref;
807
808 if (Call->paramHasAttr(ArgIdx, Attribute::ReadNone))
809 return ModRefInfo::NoModRef;
810
811 return AAResultBase::getArgModRefInfo(Call, ArgIdx);
812}
813
814static bool isIntrinsicCall(const CallBase *Call, Intrinsic::ID IID) {
815 const IntrinsicInst *II = dyn_cast<IntrinsicInst>(Call);
816 return II && II->getIntrinsicID() == IID;
817}
818
819#ifndef NDEBUG
820static const Function *getParent(const Value *V) {
821 if (const Instruction *inst = dyn_cast<Instruction>(V)) {
822 if (!inst->getParent())
823 return nullptr;
824 return inst->getParent()->getParent();
825 }
826
827 if (const Argument *arg = dyn_cast<Argument>(V))
828 return arg->getParent();
829
830 return nullptr;
831}
832
833static bool notDifferentParent(const Value *O1, const Value *O2) {
834
835 const Function *F1 = getParent(O1);
836 const Function *F2 = getParent(O2);
837
838 return !F1 || !F2 || F1 == F2;
839}
840#endif
841
842AliasResult BasicAAResult::alias(const MemoryLocation &LocA,
843 const MemoryLocation &LocB,
844 AAQueryInfo &AAQI) {
845 assert(notDifferentParent(LocA.Ptr, LocB.Ptr) &&((notDifferentParent(LocA.Ptr, LocB.Ptr) && "BasicAliasAnalysis doesn't support interprocedural queries."
) ? static_cast<void> (0) : __assert_fail ("notDifferentParent(LocA.Ptr, LocB.Ptr) && \"BasicAliasAnalysis doesn't support interprocedural queries.\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 846, __PRETTY_FUNCTION__))
846 "BasicAliasAnalysis doesn't support interprocedural queries.")((notDifferentParent(LocA.Ptr, LocB.Ptr) && "BasicAliasAnalysis doesn't support interprocedural queries."
) ? static_cast<void> (0) : __assert_fail ("notDifferentParent(LocA.Ptr, LocB.Ptr) && \"BasicAliasAnalysis doesn't support interprocedural queries.\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 846, __PRETTY_FUNCTION__))
;
847
848 // If we have a directly cached entry for these locations, we have recursed
849 // through this once, so just return the cached results. Notably, when this
850 // happens, we don't clear the cache.
851 auto CacheIt = AAQI.AliasCache.find(AAQueryInfo::LocPair(LocA, LocB));
852 if (CacheIt != AAQI.AliasCache.end())
853 return CacheIt->second;
854
855 CacheIt = AAQI.AliasCache.find(AAQueryInfo::LocPair(LocB, LocA));
856 if (CacheIt != AAQI.AliasCache.end())
857 return CacheIt->second;
858
859 AliasResult Alias = aliasCheck(LocA.Ptr, LocA.Size, LocA.AATags, LocB.Ptr,
860 LocB.Size, LocB.AATags, AAQI);
861
862 VisitedPhiBBs.clear();
863 return Alias;
864}
865
866/// Checks to see if the specified callsite can clobber the specified memory
867/// object.
868///
869/// Since we only look at local properties of this function, we really can't
870/// say much about this query. We do, however, use simple "address taken"
871/// analysis on local objects.
872ModRefInfo BasicAAResult::getModRefInfo(const CallBase *Call,
873 const MemoryLocation &Loc,
874 AAQueryInfo &AAQI) {
875 assert(notDifferentParent(Call, Loc.Ptr) &&((notDifferentParent(Call, Loc.Ptr) && "AliasAnalysis query involving multiple functions!"
) ? static_cast<void> (0) : __assert_fail ("notDifferentParent(Call, Loc.Ptr) && \"AliasAnalysis query involving multiple functions!\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 876, __PRETTY_FUNCTION__))
876 "AliasAnalysis query involving multiple functions!")((notDifferentParent(Call, Loc.Ptr) && "AliasAnalysis query involving multiple functions!"
) ? static_cast<void> (0) : __assert_fail ("notDifferentParent(Call, Loc.Ptr) && \"AliasAnalysis query involving multiple functions!\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 876, __PRETTY_FUNCTION__))
;
877
878 const Value *Object = getUnderlyingObject(Loc.Ptr);
879
880 // Calls marked 'tail' cannot read or write allocas from the current frame
881 // because the current frame might be destroyed by the time they run. However,
882 // a tail call may use an alloca with byval. Calling with byval copies the
883 // contents of the alloca into argument registers or stack slots, so there is
884 // no lifetime issue.
885 if (isa<AllocaInst>(Object))
886 if (const CallInst *CI = dyn_cast<CallInst>(Call))
887 if (CI->isTailCall() &&
888 !CI->getAttributes().hasAttrSomewhere(Attribute::ByVal))
889 return ModRefInfo::NoModRef;
890
891 // Stack restore is able to modify unescaped dynamic allocas. Assume it may
892 // modify them even though the alloca is not escaped.
893 if (auto *AI = dyn_cast<AllocaInst>(Object))
894 if (!AI->isStaticAlloca() && isIntrinsicCall(Call, Intrinsic::stackrestore))
895 return ModRefInfo::Mod;
896
897 // If the pointer is to a locally allocated object that does not escape,
898 // then the call can not mod/ref the pointer unless the call takes the pointer
899 // as an argument, and itself doesn't capture it.
900 if (!isa<Constant>(Object) && Call != Object &&
901 isNonEscapingLocalObject(Object, &AAQI.IsCapturedCache)) {
902
903 // Optimistically assume that call doesn't touch Object and check this
904 // assumption in the following loop.
905 ModRefInfo Result = ModRefInfo::NoModRef;
906 bool IsMustAlias = true;
907
908 unsigned OperandNo = 0;
909 for (auto CI = Call->data_operands_begin(), CE = Call->data_operands_end();
910 CI != CE; ++CI, ++OperandNo) {
911 // Only look at the no-capture or byval pointer arguments. If this
912 // pointer were passed to arguments that were neither of these, then it
913 // couldn't be no-capture.
914 if (!(*CI)->getType()->isPointerTy() ||
915 (!Call->doesNotCapture(OperandNo) &&
916 OperandNo < Call->getNumArgOperands() &&
917 !Call->isByValArgument(OperandNo)))
918 continue;
919
920 // Call doesn't access memory through this operand, so we don't care
921 // if it aliases with Object.
922 if (Call->doesNotAccessMemory(OperandNo))
923 continue;
924
925 // If this is a no-capture pointer argument, see if we can tell that it
926 // is impossible to alias the pointer we're checking.
927 AliasResult AR = getBestAAResults().alias(MemoryLocation(*CI),
928 MemoryLocation(Object), AAQI);
929 if (AR != MustAlias)
930 IsMustAlias = false;
931 // Operand doesn't alias 'Object', continue looking for other aliases
932 if (AR == NoAlias)
933 continue;
934 // Operand aliases 'Object', but call doesn't modify it. Strengthen
935 // initial assumption and keep looking in case if there are more aliases.
936 if (Call->onlyReadsMemory(OperandNo)) {
937 Result = setRef(Result);
938 continue;
939 }
940 // Operand aliases 'Object' but call only writes into it.
941 if (Call->doesNotReadMemory(OperandNo)) {
942 Result = setMod(Result);
943 continue;
944 }
945 // This operand aliases 'Object' and call reads and writes into it.
946 // Setting ModRef will not yield an early return below, MustAlias is not
947 // used further.
948 Result = ModRefInfo::ModRef;
949 break;
950 }
951
952 // No operand aliases, reset Must bit. Add below if at least one aliases
953 // and all aliases found are MustAlias.
954 if (isNoModRef(Result))
955 IsMustAlias = false;
956
957 // Early return if we improved mod ref information
958 if (!isModAndRefSet(Result)) {
959 if (isNoModRef(Result))
960 return ModRefInfo::NoModRef;
961 return IsMustAlias ? setMust(Result) : clearMust(Result);
962 }
963 }
964
965 // If the call is malloc/calloc like, we can assume that it doesn't
966 // modify any IR visible value. This is only valid because we assume these
967 // routines do not read values visible in the IR. TODO: Consider special
968 // casing realloc and strdup routines which access only their arguments as
969 // well. Or alternatively, replace all of this with inaccessiblememonly once
970 // that's implemented fully.
971 if (isMallocOrCallocLikeFn(Call, &TLI)) {
972 // Be conservative if the accessed pointer may alias the allocation -
973 // fallback to the generic handling below.
974 if (getBestAAResults().alias(MemoryLocation(Call), Loc, AAQI) == NoAlias)
975 return ModRefInfo::NoModRef;
976 }
977
978 // The semantics of memcpy intrinsics either exactly overlap or do not
979 // overlap, i.e., source and destination of any given memcpy are either
980 // no-alias or must-alias.
981 if (auto *Inst = dyn_cast<AnyMemCpyInst>(Call)) {
982 AliasResult SrcAA =
983 getBestAAResults().alias(MemoryLocation::getForSource(Inst), Loc, AAQI);
984 AliasResult DestAA =
985 getBestAAResults().alias(MemoryLocation::getForDest(Inst), Loc, AAQI);
986 // It's also possible for Loc to alias both src and dest, or neither.
987 ModRefInfo rv = ModRefInfo::NoModRef;
988 if (SrcAA != NoAlias)
989 rv = setRef(rv);
990 if (DestAA != NoAlias)
991 rv = setMod(rv);
992 return rv;
993 }
994
995 // While the assume intrinsic is marked as arbitrarily writing so that
996 // proper control dependencies will be maintained, it never aliases any
997 // particular memory location.
998 if (isIntrinsicCall(Call, Intrinsic::assume))
999 return ModRefInfo::NoModRef;
1000
1001 // Like assumes, guard intrinsics are also marked as arbitrarily writing so
1002 // that proper control dependencies are maintained but they never mods any
1003 // particular memory location.
1004 //
1005 // *Unlike* assumes, guard intrinsics are modeled as reading memory since the
1006 // heap state at the point the guard is issued needs to be consistent in case
1007 // the guard invokes the "deopt" continuation.
1008 if (isIntrinsicCall(Call, Intrinsic::experimental_guard))
1009 return ModRefInfo::Ref;
1010
1011 // Like assumes, invariant.start intrinsics were also marked as arbitrarily
1012 // writing so that proper control dependencies are maintained but they never
1013 // mod any particular memory location visible to the IR.
1014 // *Unlike* assumes (which are now modeled as NoModRef), invariant.start
1015 // intrinsic is now modeled as reading memory. This prevents hoisting the
1016 // invariant.start intrinsic over stores. Consider:
1017 // *ptr = 40;
1018 // *ptr = 50;
1019 // invariant_start(ptr)
1020 // int val = *ptr;
1021 // print(val);
1022 //
1023 // This cannot be transformed to:
1024 //
1025 // *ptr = 40;
1026 // invariant_start(ptr)
1027 // *ptr = 50;
1028 // int val = *ptr;
1029 // print(val);
1030 //
1031 // The transformation will cause the second store to be ignored (based on
1032 // rules of invariant.start) and print 40, while the first program always
1033 // prints 50.
1034 if (isIntrinsicCall(Call, Intrinsic::invariant_start))
1035 return ModRefInfo::Ref;
1036
1037 // The AAResultBase base class has some smarts, lets use them.
1038 return AAResultBase::getModRefInfo(Call, Loc, AAQI);
1039}
1040
1041ModRefInfo BasicAAResult::getModRefInfo(const CallBase *Call1,
1042 const CallBase *Call2,
1043 AAQueryInfo &AAQI) {
1044 // While the assume intrinsic is marked as arbitrarily writing so that
1045 // proper control dependencies will be maintained, it never aliases any
1046 // particular memory location.
1047 if (isIntrinsicCall(Call1, Intrinsic::assume) ||
1048 isIntrinsicCall(Call2, Intrinsic::assume))
1049 return ModRefInfo::NoModRef;
1050
1051 // Like assumes, guard intrinsics are also marked as arbitrarily writing so
1052 // that proper control dependencies are maintained but they never mod any
1053 // particular memory location.
1054 //
1055 // *Unlike* assumes, guard intrinsics are modeled as reading memory since the
1056 // heap state at the point the guard is issued needs to be consistent in case
1057 // the guard invokes the "deopt" continuation.
1058
1059 // NB! This function is *not* commutative, so we special case two
1060 // possibilities for guard intrinsics.
1061
1062 if (isIntrinsicCall(Call1, Intrinsic::experimental_guard))
1063 return isModSet(createModRefInfo(getModRefBehavior(Call2)))
1064 ? ModRefInfo::Ref
1065 : ModRefInfo::NoModRef;
1066
1067 if (isIntrinsicCall(Call2, Intrinsic::experimental_guard))
1068 return isModSet(createModRefInfo(getModRefBehavior(Call1)))
1069 ? ModRefInfo::Mod
1070 : ModRefInfo::NoModRef;
1071
1072 // The AAResultBase base class has some smarts, lets use them.
1073 return AAResultBase::getModRefInfo(Call1, Call2, AAQI);
1074}
1075
1076/// Provide ad-hoc rules to disambiguate accesses through two GEP operators,
1077/// both having the exact same pointer operand.
1078static AliasResult aliasSameBasePointerGEPs(const GEPOperator *GEP1,
1079 LocationSize MaybeV1Size,
1080 const GEPOperator *GEP2,
1081 LocationSize MaybeV2Size,
1082 const DataLayout &DL) {
1083 assert(GEP1->getPointerOperand()->stripPointerCastsAndInvariantGroups() ==((GEP1->getPointerOperand()->stripPointerCastsAndInvariantGroups
() == GEP2->getPointerOperand()->stripPointerCastsAndInvariantGroups
() && GEP1->getPointerOperandType() == GEP2->getPointerOperandType
() && "Expected GEPs with the same pointer operand") ?
static_cast<void> (0) : __assert_fail ("GEP1->getPointerOperand()->stripPointerCastsAndInvariantGroups() == GEP2->getPointerOperand()->stripPointerCastsAndInvariantGroups() && GEP1->getPointerOperandType() == GEP2->getPointerOperandType() && \"Expected GEPs with the same pointer operand\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1086, __PRETTY_FUNCTION__))
1084 GEP2->getPointerOperand()->stripPointerCastsAndInvariantGroups() &&((GEP1->getPointerOperand()->stripPointerCastsAndInvariantGroups
() == GEP2->getPointerOperand()->stripPointerCastsAndInvariantGroups
() && GEP1->getPointerOperandType() == GEP2->getPointerOperandType
() && "Expected GEPs with the same pointer operand") ?
static_cast<void> (0) : __assert_fail ("GEP1->getPointerOperand()->stripPointerCastsAndInvariantGroups() == GEP2->getPointerOperand()->stripPointerCastsAndInvariantGroups() && GEP1->getPointerOperandType() == GEP2->getPointerOperandType() && \"Expected GEPs with the same pointer operand\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1086, __PRETTY_FUNCTION__))
1085 GEP1->getPointerOperandType() == GEP2->getPointerOperandType() &&((GEP1->getPointerOperand()->stripPointerCastsAndInvariantGroups
() == GEP2->getPointerOperand()->stripPointerCastsAndInvariantGroups
() && GEP1->getPointerOperandType() == GEP2->getPointerOperandType
() && "Expected GEPs with the same pointer operand") ?
static_cast<void> (0) : __assert_fail ("GEP1->getPointerOperand()->stripPointerCastsAndInvariantGroups() == GEP2->getPointerOperand()->stripPointerCastsAndInvariantGroups() && GEP1->getPointerOperandType() == GEP2->getPointerOperandType() && \"Expected GEPs with the same pointer operand\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1086, __PRETTY_FUNCTION__))
1086 "Expected GEPs with the same pointer operand")((GEP1->getPointerOperand()->stripPointerCastsAndInvariantGroups
() == GEP2->getPointerOperand()->stripPointerCastsAndInvariantGroups
() && GEP1->getPointerOperandType() == GEP2->getPointerOperandType
() && "Expected GEPs with the same pointer operand") ?
static_cast<void> (0) : __assert_fail ("GEP1->getPointerOperand()->stripPointerCastsAndInvariantGroups() == GEP2->getPointerOperand()->stripPointerCastsAndInvariantGroups() && GEP1->getPointerOperandType() == GEP2->getPointerOperandType() && \"Expected GEPs with the same pointer operand\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1086, __PRETTY_FUNCTION__))
;
1087
1088 // Try to determine whether GEP1 and GEP2 index through arrays, into structs,
1089 // such that the struct field accesses provably cannot alias.
1090 // We also need at least two indices (the pointer, and the struct field).
1091 if (GEP1->getNumIndices() != GEP2->getNumIndices() ||
1092 GEP1->getNumIndices() < 2)
1093 return MayAlias;
1094
1095 // If we don't know the size of the accesses through both GEPs, we can't
1096 // determine whether the struct fields accessed can't alias.
1097 if (MaybeV1Size == LocationSize::unknown() ||
1098 MaybeV2Size == LocationSize::unknown())
1099 return MayAlias;
1100
1101 const uint64_t V1Size = MaybeV1Size.getValue();
1102 const uint64_t V2Size = MaybeV2Size.getValue();
1103
1104 ConstantInt *C1 =
1105 dyn_cast<ConstantInt>(GEP1->getOperand(GEP1->getNumOperands() - 1));
1106 ConstantInt *C2 =
1107 dyn_cast<ConstantInt>(GEP2->getOperand(GEP2->getNumOperands() - 1));
1108
1109 // If the last (struct) indices are constants and are equal, the other indices
1110 // might be also be dynamically equal, so the GEPs can alias.
1111 if (C1 && C2) {
1112 unsigned BitWidth = std::max(C1->getBitWidth(), C2->getBitWidth());
1113 if (C1->getValue().sextOrSelf(BitWidth) ==
1114 C2->getValue().sextOrSelf(BitWidth))
1115 return MayAlias;
1116 }
1117
1118 // Find the last-indexed type of the GEP, i.e., the type you'd get if
1119 // you stripped the last index.
1120 // On the way, look at each indexed type. If there's something other
1121 // than an array, different indices can lead to different final types.
1122 SmallVector<Value *, 8> IntermediateIndices;
1123
1124 // Insert the first index; we don't need to check the type indexed
1125 // through it as it only drops the pointer indirection.
1126 assert(GEP1->getNumIndices() > 1 && "Not enough GEP indices to examine")((GEP1->getNumIndices() > 1 && "Not enough GEP indices to examine"
) ? static_cast<void> (0) : __assert_fail ("GEP1->getNumIndices() > 1 && \"Not enough GEP indices to examine\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1126, __PRETTY_FUNCTION__))
;
1127 IntermediateIndices.push_back(GEP1->getOperand(1));
1128
1129 // Insert all the remaining indices but the last one.
1130 // Also, check that they all index through arrays.
1131 for (unsigned i = 1, e = GEP1->getNumIndices() - 1; i != e; ++i) {
1132 if (!isa<ArrayType>(GetElementPtrInst::getIndexedType(
1133 GEP1->getSourceElementType(), IntermediateIndices)))
1134 return MayAlias;
1135 IntermediateIndices.push_back(GEP1->getOperand(i + 1));
1136 }
1137
1138 auto *Ty = GetElementPtrInst::getIndexedType(
1139 GEP1->getSourceElementType(), IntermediateIndices);
1140 StructType *LastIndexedStruct = dyn_cast<StructType>(Ty);
1141
1142 if (isa<ArrayType>(Ty) || isa<VectorType>(Ty)) {
1143 // We know that:
1144 // - both GEPs begin indexing from the exact same pointer;
1145 // - the last indices in both GEPs are constants, indexing into a sequential
1146 // type (array or vector);
1147 // - both GEPs only index through arrays prior to that.
1148 //
1149 // Because array indices greater than the number of elements are valid in
1150 // GEPs, unless we know the intermediate indices are identical between
1151 // GEP1 and GEP2 we cannot guarantee that the last indexed arrays don't
1152 // partially overlap. We also need to check that the loaded size matches
1153 // the element size, otherwise we could still have overlap.
1154 Type *LastElementTy = GetElementPtrInst::getTypeAtIndex(Ty, (uint64_t)0);
1155 const uint64_t ElementSize =
1156 DL.getTypeStoreSize(LastElementTy).getFixedSize();
1157 if (V1Size != ElementSize || V2Size != ElementSize)
1158 return MayAlias;
1159
1160 for (unsigned i = 0, e = GEP1->getNumIndices() - 1; i != e; ++i)
1161 if (GEP1->getOperand(i + 1) != GEP2->getOperand(i + 1))
1162 return MayAlias;
1163
1164 // Now we know that the array/pointer that GEP1 indexes into and that
1165 // that GEP2 indexes into must either precisely overlap or be disjoint.
1166 // Because they cannot partially overlap and because fields in an array
1167 // cannot overlap, if we can prove the final indices are different between
1168 // GEP1 and GEP2, we can conclude GEP1 and GEP2 don't alias.
1169
1170 // If the last indices are constants, we've already checked they don't
1171 // equal each other so we can exit early.
1172 if (C1 && C2)
1173 return NoAlias;
1174 {
1175 Value *GEP1LastIdx = GEP1->getOperand(GEP1->getNumOperands() - 1);
1176 Value *GEP2LastIdx = GEP2->getOperand(GEP2->getNumOperands() - 1);
1177 if (isa<PHINode>(GEP1LastIdx) || isa<PHINode>(GEP2LastIdx)) {
1178 // If one of the indices is a PHI node, be safe and only use
1179 // computeKnownBits so we don't make any assumptions about the
1180 // relationships between the two indices. This is important if we're
1181 // asking about values from different loop iterations. See PR32314.
1182 // TODO: We may be able to change the check so we only do this when
1183 // we definitely looked through a PHINode.
1184 if (GEP1LastIdx != GEP2LastIdx &&
1185 GEP1LastIdx->getType() == GEP2LastIdx->getType()) {
1186 KnownBits Known1 = computeKnownBits(GEP1LastIdx, DL);
1187 KnownBits Known2 = computeKnownBits(GEP2LastIdx, DL);
1188 if (Known1.Zero.intersects(Known2.One) ||
1189 Known1.One.intersects(Known2.Zero))
1190 return NoAlias;
1191 }
1192 } else if (isKnownNonEqual(GEP1LastIdx, GEP2LastIdx, DL))
1193 return NoAlias;
1194 }
1195 return MayAlias;
1196 } else if (!LastIndexedStruct || !C1 || !C2) {
1197 return MayAlias;
1198 }
1199
1200 if (C1->getValue().getActiveBits() > 64 ||
1201 C2->getValue().getActiveBits() > 64)
1202 return MayAlias;
1203
1204 // We know that:
1205 // - both GEPs begin indexing from the exact same pointer;
1206 // - the last indices in both GEPs are constants, indexing into a struct;
1207 // - said indices are different, hence, the pointed-to fields are different;
1208 // - both GEPs only index through arrays prior to that.
1209 //
1210 // This lets us determine that the struct that GEP1 indexes into and the
1211 // struct that GEP2 indexes into must either precisely overlap or be
1212 // completely disjoint. Because they cannot partially overlap, indexing into
1213 // different non-overlapping fields of the struct will never alias.
1214
1215 // Therefore, the only remaining thing needed to show that both GEPs can't
1216 // alias is that the fields are not overlapping.
1217 const StructLayout *SL = DL.getStructLayout(LastIndexedStruct);
1218 const uint64_t StructSize = SL->getSizeInBytes();
1219 const uint64_t V1Off = SL->getElementOffset(C1->getZExtValue());
1220 const uint64_t V2Off = SL->getElementOffset(C2->getZExtValue());
1221
1222 auto EltsDontOverlap = [StructSize](uint64_t V1Off, uint64_t V1Size,
1223 uint64_t V2Off, uint64_t V2Size) {
1224 return V1Off < V2Off && V1Off + V1Size <= V2Off &&
1225 ((V2Off + V2Size <= StructSize) ||
1226 (V2Off + V2Size - StructSize <= V1Off));
1227 };
1228
1229 if (EltsDontOverlap(V1Off, V1Size, V2Off, V2Size) ||
1230 EltsDontOverlap(V2Off, V2Size, V1Off, V1Size))
1231 return NoAlias;
1232
1233 return MayAlias;
1234}
1235
1236// If a we have (a) a GEP and (b) a pointer based on an alloca, and the
1237// beginning of the object the GEP points would have a negative offset with
1238// repsect to the alloca, that means the GEP can not alias pointer (b).
1239// Note that the pointer based on the alloca may not be a GEP. For
1240// example, it may be the alloca itself.
1241// The same applies if (b) is based on a GlobalVariable. Note that just being
1242// based on isIdentifiedObject() is not enough - we need an identified object
1243// that does not permit access to negative offsets. For example, a negative
1244// offset from a noalias argument or call can be inbounds w.r.t the actual
1245// underlying object.
1246//
1247// For example, consider:
1248//
1249// struct { int f0, int f1, ...} foo;
1250// foo alloca;
1251// foo* random = bar(alloca);
1252// int *f0 = &alloca.f0
1253// int *f1 = &random->f1;
1254//
1255// Which is lowered, approximately, to:
1256//
1257// %alloca = alloca %struct.foo
1258// %random = call %struct.foo* @random(%struct.foo* %alloca)
1259// %f0 = getelementptr inbounds %struct, %struct.foo* %alloca, i32 0, i32 0
1260// %f1 = getelementptr inbounds %struct, %struct.foo* %random, i32 0, i32 1
1261//
1262// Assume %f1 and %f0 alias. Then %f1 would point into the object allocated
1263// by %alloca. Since the %f1 GEP is inbounds, that means %random must also
1264// point into the same object. But since %f0 points to the beginning of %alloca,
1265// the highest %f1 can be is (%alloca + 3). This means %random can not be higher
1266// than (%alloca - 1), and so is not inbounds, a contradiction.
1267bool BasicAAResult::isGEPBaseAtNegativeOffset(const GEPOperator *GEPOp,
1268 const DecomposedGEP &DecompGEP, const DecomposedGEP &DecompObject,
1269 LocationSize MaybeObjectAccessSize) {
1270 // If the object access size is unknown, or the GEP isn't inbounds, bail.
1271 if (MaybeObjectAccessSize == LocationSize::unknown() || !GEPOp->isInBounds())
1272 return false;
1273
1274 const uint64_t ObjectAccessSize = MaybeObjectAccessSize.getValue();
1275
1276 // We need the object to be an alloca or a globalvariable, and want to know
1277 // the offset of the pointer from the object precisely, so no variable
1278 // indices are allowed.
1279 if (!(isa<AllocaInst>(DecompObject.Base) ||
1280 isa<GlobalVariable>(DecompObject.Base)) ||
1281 !DecompObject.VarIndices.empty())
1282 return false;
1283
1284 APInt ObjectBaseOffset = DecompObject.StructOffset +
1285 DecompObject.OtherOffset;
1286
1287 // If the GEP has no variable indices, we know the precise offset
1288 // from the base, then use it. If the GEP has variable indices,
1289 // we can't get exact GEP offset to identify pointer alias. So return
1290 // false in that case.
1291 if (!DecompGEP.VarIndices.empty())
1292 return false;
1293
1294 APInt GEPBaseOffset = DecompGEP.StructOffset;
1295 GEPBaseOffset += DecompGEP.OtherOffset;
1296
1297 return GEPBaseOffset.sge(ObjectBaseOffset + (int64_t)ObjectAccessSize);
1298}
1299
1300/// Provides a bunch of ad-hoc rules to disambiguate a GEP instruction against
1301/// another pointer.
1302///
1303/// We know that V1 is a GEP, but we don't know anything about V2.
1304/// UnderlyingV1 is getUnderlyingObject(GEP1), UnderlyingV2 is the same for
1305/// V2.
1306AliasResult BasicAAResult::aliasGEP(
1307 const GEPOperator *GEP1, LocationSize V1Size, const AAMDNodes &V1AAInfo,
1308 const Value *V2, LocationSize V2Size, const AAMDNodes &V2AAInfo,
1309 const Value *UnderlyingV1, const Value *UnderlyingV2, AAQueryInfo &AAQI) {
1310 DecomposedGEP DecompGEP1, DecompGEP2;
1311 unsigned MaxPointerSize = getMaxPointerSize(DL);
1312 DecompGEP1.StructOffset = DecompGEP1.OtherOffset = APInt(MaxPointerSize, 0);
1313 DecompGEP2.StructOffset = DecompGEP2.OtherOffset = APInt(MaxPointerSize, 0);
1314 DecompGEP1.HasCompileTimeConstantScale =
1315 DecompGEP2.HasCompileTimeConstantScale = true;
1316
1317 bool GEP1MaxLookupReached =
1318 DecomposeGEPExpression(GEP1, DecompGEP1, DL, &AC, DT);
1319 bool GEP2MaxLookupReached =
1320 DecomposeGEPExpression(V2, DecompGEP2, DL, &AC, DT);
1321
1322 // Don't attempt to analyze the decomposed GEP if index scale is not a
1323 // compile-time constant.
1324 if (!DecompGEP1.HasCompileTimeConstantScale ||
1325 !DecompGEP2.HasCompileTimeConstantScale)
1326 return MayAlias;
1327
1328 APInt GEP1BaseOffset = DecompGEP1.StructOffset + DecompGEP1.OtherOffset;
1329 APInt GEP2BaseOffset = DecompGEP2.StructOffset + DecompGEP2.OtherOffset;
1330
1331 assert(DecompGEP1.Base == UnderlyingV1 && DecompGEP2.Base == UnderlyingV2 &&((DecompGEP1.Base == UnderlyingV1 && DecompGEP2.Base ==
UnderlyingV2 && "DecomposeGEPExpression returned a result different from "
"getUnderlyingObject") ? static_cast<void> (0) : __assert_fail
("DecompGEP1.Base == UnderlyingV1 && DecompGEP2.Base == UnderlyingV2 && \"DecomposeGEPExpression returned a result different from \" \"getUnderlyingObject\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1333, __PRETTY_FUNCTION__))
1332 "DecomposeGEPExpression returned a result different from "((DecompGEP1.Base == UnderlyingV1 && DecompGEP2.Base ==
UnderlyingV2 && "DecomposeGEPExpression returned a result different from "
"getUnderlyingObject") ? static_cast<void> (0) : __assert_fail
("DecompGEP1.Base == UnderlyingV1 && DecompGEP2.Base == UnderlyingV2 && \"DecomposeGEPExpression returned a result different from \" \"getUnderlyingObject\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1333, __PRETTY_FUNCTION__))
1333 "getUnderlyingObject")((DecompGEP1.Base == UnderlyingV1 && DecompGEP2.Base ==
UnderlyingV2 && "DecomposeGEPExpression returned a result different from "
"getUnderlyingObject") ? static_cast<void> (0) : __assert_fail
("DecompGEP1.Base == UnderlyingV1 && DecompGEP2.Base == UnderlyingV2 && \"DecomposeGEPExpression returned a result different from \" \"getUnderlyingObject\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1333, __PRETTY_FUNCTION__))
;
1334
1335 // If the GEP's offset relative to its base is such that the base would
1336 // fall below the start of the object underlying V2, then the GEP and V2
1337 // cannot alias.
1338 if (!GEP1MaxLookupReached && !GEP2MaxLookupReached &&
1339 isGEPBaseAtNegativeOffset(GEP1, DecompGEP1, DecompGEP2, V2Size))
1340 return NoAlias;
1341 // If we have two gep instructions with must-alias or not-alias'ing base
1342 // pointers, figure out if the indexes to the GEP tell us anything about the
1343 // derived pointer.
1344 if (const GEPOperator *GEP2 = dyn_cast<GEPOperator>(V2)) {
1345 // Check for the GEP base being at a negative offset, this time in the other
1346 // direction.
1347 if (!GEP1MaxLookupReached && !GEP2MaxLookupReached &&
1348 isGEPBaseAtNegativeOffset(GEP2, DecompGEP2, DecompGEP1, V1Size))
1349 return NoAlias;
1350 // Do the base pointers alias?
1351 AliasResult BaseAlias =
1352 aliasCheck(UnderlyingV1, LocationSize::unknown(), AAMDNodes(),
1353 UnderlyingV2, LocationSize::unknown(), AAMDNodes(), AAQI);
1354
1355 // Check for geps of non-aliasing underlying pointers where the offsets are
1356 // identical.
1357 if ((BaseAlias == MayAlias) && V1Size == V2Size) {
1358 // Do the base pointers alias assuming type and size.
1359 AliasResult PreciseBaseAlias = aliasCheck(
1360 UnderlyingV1, V1Size, V1AAInfo, UnderlyingV2, V2Size, V2AAInfo, AAQI);
1361 if (PreciseBaseAlias == NoAlias) {
1362 // See if the computed offset from the common pointer tells us about the
1363 // relation of the resulting pointer.
1364 // If the max search depth is reached the result is undefined
1365 if (GEP2MaxLookupReached || GEP1MaxLookupReached)
1366 return MayAlias;
1367
1368 // Same offsets.
1369 if (GEP1BaseOffset == GEP2BaseOffset &&
1370 DecompGEP1.VarIndices == DecompGEP2.VarIndices)
1371 return NoAlias;
1372 }
1373 }
1374
1375 // If we get a No or May, then return it immediately, no amount of analysis
1376 // will improve this situation.
1377 if (BaseAlias != MustAlias) {
1378 assert(BaseAlias == NoAlias || BaseAlias == MayAlias)((BaseAlias == NoAlias || BaseAlias == MayAlias) ? static_cast
<void> (0) : __assert_fail ("BaseAlias == NoAlias || BaseAlias == MayAlias"
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1378, __PRETTY_FUNCTION__))
;
1379 return BaseAlias;
1380 }
1381
1382 // Otherwise, we have a MustAlias. Since the base pointers alias each other
1383 // exactly, see if the computed offset from the common pointer tells us
1384 // about the relation of the resulting pointer.
1385 // If we know the two GEPs are based off of the exact same pointer (and not
1386 // just the same underlying object), see if that tells us anything about
1387 // the resulting pointers.
1388 if (GEP1->getPointerOperand()->stripPointerCastsAndInvariantGroups() ==
1389 GEP2->getPointerOperand()->stripPointerCastsAndInvariantGroups() &&
1390 GEP1->getPointerOperandType() == GEP2->getPointerOperandType()) {
1391 AliasResult R = aliasSameBasePointerGEPs(GEP1, V1Size, GEP2, V2Size, DL);
1392 // If we couldn't find anything interesting, don't abandon just yet.
1393 if (R != MayAlias)
1394 return R;
1395 }
1396
1397 // If the max search depth is reached, the result is undefined
1398 if (GEP2MaxLookupReached || GEP1MaxLookupReached)
1399 return MayAlias;
1400
1401 // Subtract the GEP2 pointer from the GEP1 pointer to find out their
1402 // symbolic difference.
1403 GEP1BaseOffset -= GEP2BaseOffset;
1404 GetIndexDifference(DecompGEP1.VarIndices, DecompGEP2.VarIndices);
1405
1406 } else {
1407 // Check to see if these two pointers are related by the getelementptr
1408 // instruction. If one pointer is a GEP with a non-zero index of the other
1409 // pointer, we know they cannot alias.
1410
1411 // If both accesses are unknown size, we can't do anything useful here.
1412 if (V1Size == LocationSize::unknown() && V2Size == LocationSize::unknown())
1413 return MayAlias;
1414
1415 AliasResult R = aliasCheck(UnderlyingV1, LocationSize::unknown(),
1416 AAMDNodes(), V2, LocationSize::unknown(),
1417 V2AAInfo, AAQI, nullptr, UnderlyingV2);
1418 if (R != MustAlias) {
1419 // If V2 may alias GEP base pointer, conservatively returns MayAlias.
1420 // If V2 is known not to alias GEP base pointer, then the two values
1421 // cannot alias per GEP semantics: "Any memory access must be done through
1422 // a pointer value associated with an address range of the memory access,
1423 // otherwise the behavior is undefined.".
1424 assert(R == NoAlias || R == MayAlias)((R == NoAlias || R == MayAlias) ? static_cast<void> (0
) : __assert_fail ("R == NoAlias || R == MayAlias", "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1424, __PRETTY_FUNCTION__))
;
1425 return R;
1426 }
1427
1428 // If the max search depth is reached the result is undefined
1429 if (GEP1MaxLookupReached)
1430 return MayAlias;
1431 }
1432
1433 // In the two GEP Case, if there is no difference in the offsets of the
1434 // computed pointers, the resultant pointers are a must alias. This
1435 // happens when we have two lexically identical GEP's (for example).
1436 //
1437 // In the other case, if we have getelementptr <ptr>, 0, 0, 0, 0, ... and V2
1438 // must aliases the GEP, the end result is a must alias also.
1439 if (GEP1BaseOffset == 0 && DecompGEP1.VarIndices.empty())
1440 return MustAlias;
1441
1442 // If there is a constant difference between the pointers, but the difference
1443 // is less than the size of the associated memory object, then we know
1444 // that the objects are partially overlapping. If the difference is
1445 // greater, we know they do not overlap.
1446 if (GEP1BaseOffset != 0 && DecompGEP1.VarIndices.empty()) {
1447 if (GEP1BaseOffset.sge(0)) {
1448 if (V2Size != LocationSize::unknown()) {
1449 if (GEP1BaseOffset.ult(V2Size.getValue()))
1450 return PartialAlias;
1451 return NoAlias;
1452 }
1453 } else {
1454 // We have the situation where:
1455 // + +
1456 // | BaseOffset |
1457 // ---------------->|
1458 // |-->V1Size |-------> V2Size
1459 // GEP1 V2
1460 // We need to know that V2Size is not unknown, otherwise we might have
1461 // stripped a gep with negative index ('gep <ptr>, -1, ...).
1462 if (V1Size != LocationSize::unknown() &&
1463 V2Size != LocationSize::unknown()) {
1464 if ((-GEP1BaseOffset).ult(V1Size.getValue()))
1465 return PartialAlias;
1466 return NoAlias;
1467 }
1468 }
1469 }
1470
1471 if (!DecompGEP1.VarIndices.empty()) {
1472 APInt Modulo(MaxPointerSize, 0);
1473 bool AllPositive = true;
1474 for (unsigned i = 0, e = DecompGEP1.VarIndices.size(); i != e; ++i) {
1475
1476 // Try to distinguish something like &A[i][1] against &A[42][0].
1477 // Grab the least significant bit set in any of the scales. We
1478 // don't need std::abs here (even if the scale's negative) as we'll
1479 // be ^'ing Modulo with itself later.
1480 Modulo |= DecompGEP1.VarIndices[i].Scale;
1481
1482 if (AllPositive) {
1483 // If the Value could change between cycles, then any reasoning about
1484 // the Value this cycle may not hold in the next cycle. We'll just
1485 // give up if we can't determine conditions that hold for every cycle:
1486 const Value *V = DecompGEP1.VarIndices[i].V;
1487
1488 KnownBits Known =
1489 computeKnownBits(V, DL, 0, &AC, dyn_cast<Instruction>(GEP1), DT);
1490 bool SignKnownZero = Known.isNonNegative();
1491 bool SignKnownOne = Known.isNegative();
1492
1493 // Zero-extension widens the variable, and so forces the sign
1494 // bit to zero.
1495 bool IsZExt = DecompGEP1.VarIndices[i].ZExtBits > 0 || isa<ZExtInst>(V);
1496 SignKnownZero |= IsZExt;
1497 SignKnownOne &= !IsZExt;
1498
1499 // If the variable begins with a zero then we know it's
1500 // positive, regardless of whether the value is signed or
1501 // unsigned.
1502 APInt Scale = DecompGEP1.VarIndices[i].Scale;
1503 AllPositive =
1504 (SignKnownZero && Scale.sge(0)) || (SignKnownOne && Scale.slt(0));
1505 }
1506 }
1507
1508 Modulo = Modulo ^ (Modulo & (Modulo - 1));
1509
1510 // We can compute the difference between the two addresses
1511 // mod Modulo. Check whether that difference guarantees that the
1512 // two locations do not alias.
1513 APInt ModOffset = GEP1BaseOffset & (Modulo - 1);
1514 if (V1Size != LocationSize::unknown() &&
1515 V2Size != LocationSize::unknown() && ModOffset.uge(V2Size.getValue()) &&
1516 (Modulo - ModOffset).uge(V1Size.getValue()))
1517 return NoAlias;
1518
1519 // If we know all the variables are positive, then GEP1 >= GEP1BasePtr.
1520 // If GEP1BasePtr > V2 (GEP1BaseOffset > 0) then we know the pointers
1521 // don't alias if V2Size can fit in the gap between V2 and GEP1BasePtr.
1522 if (AllPositive && GEP1BaseOffset.sgt(0) &&
1523 V2Size != LocationSize::unknown() &&
1524 GEP1BaseOffset.uge(V2Size.getValue()))
1525 return NoAlias;
1526
1527 if (constantOffsetHeuristic(DecompGEP1.VarIndices, V1Size, V2Size,
1528 GEP1BaseOffset, &AC, DT))
1529 return NoAlias;
1530 }
1531
1532 // Statically, we can see that the base objects are the same, but the
1533 // pointers have dynamic offsets which we can't resolve. And none of our
1534 // little tricks above worked.
1535 return MayAlias;
1536}
1537
1538static AliasResult MergeAliasResults(AliasResult A, AliasResult B) {
1539 // If the results agree, take it.
1540 if (A == B)
1541 return A;
1542 // A mix of PartialAlias and MustAlias is PartialAlias.
1543 if ((A == PartialAlias && B == MustAlias) ||
1544 (B == PartialAlias && A == MustAlias))
1545 return PartialAlias;
1546 // Otherwise, we don't know anything.
1547 return MayAlias;
1548}
1549
1550/// Provides a bunch of ad-hoc rules to disambiguate a Select instruction
1551/// against another.
1552AliasResult
1553BasicAAResult::aliasSelect(const SelectInst *SI, LocationSize SISize,
1554 const AAMDNodes &SIAAInfo, const Value *V2,
1555 LocationSize V2Size, const AAMDNodes &V2AAInfo,
1556 const Value *UnderV2, AAQueryInfo &AAQI) {
1557 // If the values are Selects with the same condition, we can do a more precise
1558 // check: just check for aliases between the values on corresponding arms.
1559 if (const SelectInst *SI2 = dyn_cast<SelectInst>(V2))
1560 if (SI->getCondition() == SI2->getCondition()) {
1561 AliasResult Alias =
1562 aliasCheck(SI->getTrueValue(), SISize, SIAAInfo, SI2->getTrueValue(),
1563 V2Size, V2AAInfo, AAQI);
1564 if (Alias == MayAlias)
1565 return MayAlias;
1566 AliasResult ThisAlias =
1567 aliasCheck(SI->getFalseValue(), SISize, SIAAInfo,
1568 SI2->getFalseValue(), V2Size, V2AAInfo, AAQI);
1569 return MergeAliasResults(ThisAlias, Alias);
1570 }
1571
1572 // If both arms of the Select node NoAlias or MustAlias V2, then returns
1573 // NoAlias / MustAlias. Otherwise, returns MayAlias.
1574 AliasResult Alias = aliasCheck(V2, V2Size, V2AAInfo, SI->getTrueValue(),
1575 SISize, SIAAInfo, AAQI, UnderV2);
1576 if (Alias == MayAlias)
1577 return MayAlias;
1578
1579 AliasResult ThisAlias = aliasCheck(V2, V2Size, V2AAInfo, SI->getFalseValue(),
1580 SISize, SIAAInfo, AAQI, UnderV2);
1581 return MergeAliasResults(ThisAlias, Alias);
1582}
1583
1584/// Provide a bunch of ad-hoc rules to disambiguate a PHI instruction against
1585/// another.
1586AliasResult BasicAAResult::aliasPHI(const PHINode *PN, LocationSize PNSize,
1587 const AAMDNodes &PNAAInfo, const Value *V2,
1588 LocationSize V2Size,
1589 const AAMDNodes &V2AAInfo,
1590 const Value *UnderV2, AAQueryInfo &AAQI) {
1591 // Track phi nodes we have visited. We use this information when we determine
1592 // value equivalence.
1593 VisitedPhiBBs.insert(PN->getParent());
1594
1595 // If the values are PHIs in the same block, we can do a more precise
1596 // as well as efficient check: just check for aliases between the values
1597 // on corresponding edges.
1598 if (const PHINode *PN2 = dyn_cast<PHINode>(V2))
1599 if (PN2->getParent() == PN->getParent()) {
1600 AAQueryInfo::LocPair Locs(MemoryLocation(PN, PNSize, PNAAInfo),
1601 MemoryLocation(V2, V2Size, V2AAInfo));
1602 if (PN > V2)
1603 std::swap(Locs.first, Locs.second);
1604 // Analyse the PHIs' inputs under the assumption that the PHIs are
1605 // NoAlias.
1606 // If the PHIs are May/MustAlias there must be (recursively) an input
1607 // operand from outside the PHIs' cycle that is MayAlias/MustAlias or
1608 // there must be an operation on the PHIs within the PHIs' value cycle
1609 // that causes a MayAlias.
1610 // Pretend the phis do not alias.
1611 AliasResult Alias = NoAlias;
1612 AliasResult OrigAliasResult;
1613 {
1614 // Limited lifetime iterator invalidated by the aliasCheck call below.
1615 auto CacheIt = AAQI.AliasCache.find(Locs);
1616 assert((CacheIt != AAQI.AliasCache.end()) &&(((CacheIt != AAQI.AliasCache.end()) && "There must exist an entry for the phi node"
) ? static_cast<void> (0) : __assert_fail ("(CacheIt != AAQI.AliasCache.end()) && \"There must exist an entry for the phi node\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1617, __PRETTY_FUNCTION__))
1617 "There must exist an entry for the phi node")(((CacheIt != AAQI.AliasCache.end()) && "There must exist an entry for the phi node"
) ? static_cast<void> (0) : __assert_fail ("(CacheIt != AAQI.AliasCache.end()) && \"There must exist an entry for the phi node\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1617, __PRETTY_FUNCTION__))
;
1618 OrigAliasResult = CacheIt->second;
1619 CacheIt->second = NoAlias;
1620 }
1621
1622 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
1623 AliasResult ThisAlias =
1624 aliasCheck(PN->getIncomingValue(i), PNSize, PNAAInfo,
1625 PN2->getIncomingValueForBlock(PN->getIncomingBlock(i)),
1626 V2Size, V2AAInfo, AAQI);
1627 Alias = MergeAliasResults(ThisAlias, Alias);
1628 if (Alias == MayAlias)
1629 break;
1630 }
1631
1632 // Reset if speculation failed.
1633 if (Alias != NoAlias) {
1634 auto Pair =
1635 AAQI.AliasCache.insert(std::make_pair(Locs, OrigAliasResult));
1636 assert(!Pair.second && "Entry must have existed")((!Pair.second && "Entry must have existed") ? static_cast
<void> (0) : __assert_fail ("!Pair.second && \"Entry must have existed\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1636, __PRETTY_FUNCTION__))
;
1637 Pair.first->second = OrigAliasResult;
1638 }
1639 return Alias;
1640 }
1641
1642 SmallVector<Value *, 4> V1Srcs;
1643 // For a recursive phi, that recurses through a contant gep, we can perform
1644 // aliasing calculations using the other phi operands with an unknown size to
1645 // specify that an unknown number of elements after the initial value are
1646 // potentially accessed.
1647 bool isRecursive = false;
1648 auto CheckForRecPhi = [&](Value *PV) {
1649 if (!EnableRecPhiAnalysis)
1650 return false;
1651 if (GEPOperator *PVGEP = dyn_cast<GEPOperator>(PV)) {
1652 // Check whether the incoming value is a GEP that advances the pointer
1653 // result of this PHI node (e.g. in a loop). If this is the case, we
1654 // would recurse and always get a MayAlias. Handle this case specially
1655 // below. We need to ensure that the phi is inbounds and has a constant
1656 // positive operand so that we can check for alias with the initial value
1657 // and an unknown but positive size.
1658 if (PVGEP->getPointerOperand() == PN && PVGEP->isInBounds() &&
1659 PVGEP->getNumIndices() == 1 && isa<ConstantInt>(PVGEP->idx_begin()) &&
1660 !cast<ConstantInt>(PVGEP->idx_begin())->isNegative()) {
1661 isRecursive = true;
1662 return true;
1663 }
1664 }
1665 return false;
1666 };
1667
1668 if (PV) {
1669 // If we have PhiValues then use it to get the underlying phi values.
1670 const PhiValues::ValueSet &PhiValueSet = PV->getValuesForPhi(PN);
1671 // If we have more phi values than the search depth then return MayAlias
1672 // conservatively to avoid compile time explosion. The worst possible case
1673 // is if both sides are PHI nodes. In which case, this is O(m x n) time
1674 // where 'm' and 'n' are the number of PHI sources.
1675 if (PhiValueSet.size() > MaxLookupSearchDepth)
1676 return MayAlias;
1677 // Add the values to V1Srcs
1678 for (Value *PV1 : PhiValueSet) {
1679 if (CheckForRecPhi(PV1))
1680 continue;
1681 V1Srcs.push_back(PV1);
1682 }
1683 } else {
1684 // If we don't have PhiInfo then just look at the operands of the phi itself
1685 // FIXME: Remove this once we can guarantee that we have PhiInfo always
1686 SmallPtrSet<Value *, 4> UniqueSrc;
1687 for (Value *PV1 : PN->incoming_values()) {
1688 if (isa<PHINode>(PV1))
1689 // If any of the source itself is a PHI, return MayAlias conservatively
1690 // to avoid compile time explosion. The worst possible case is if both
1691 // sides are PHI nodes. In which case, this is O(m x n) time where 'm'
1692 // and 'n' are the number of PHI sources.
1693 return MayAlias;
1694
1695 if (CheckForRecPhi(PV1))
1696 continue;
1697
1698 if (UniqueSrc.insert(PV1).second)
1699 V1Srcs.push_back(PV1);
1700 }
1701 }
1702
1703 // If V1Srcs is empty then that means that the phi has no underlying non-phi
1704 // value. This should only be possible in blocks unreachable from the entry
1705 // block, but return MayAlias just in case.
1706 if (V1Srcs.empty())
1707 return MayAlias;
1708
1709 // If this PHI node is recursive, set the size of the accessed memory to
1710 // unknown to represent all the possible values the GEP could advance the
1711 // pointer to.
1712 if (isRecursive)
1713 PNSize = LocationSize::unknown();
1714
1715 AliasResult Alias = aliasCheck(V2, V2Size, V2AAInfo, V1Srcs[0], PNSize,
1716 PNAAInfo, AAQI, UnderV2);
1717
1718 // Early exit if the check of the first PHI source against V2 is MayAlias.
1719 // Other results are not possible.
1720 if (Alias == MayAlias)
1721 return MayAlias;
1722 // With recursive phis we cannot guarantee that MustAlias/PartialAlias will
1723 // remain valid to all elements and needs to conservatively return MayAlias.
1724 if (isRecursive && Alias != NoAlias)
1725 return MayAlias;
1726
1727 // If all sources of the PHI node NoAlias or MustAlias V2, then returns
1728 // NoAlias / MustAlias. Otherwise, returns MayAlias.
1729 for (unsigned i = 1, e = V1Srcs.size(); i != e; ++i) {
1730 Value *V = V1Srcs[i];
1731
1732 AliasResult ThisAlias =
1733 aliasCheck(V2, V2Size, V2AAInfo, V, PNSize, PNAAInfo, AAQI, UnderV2);
1734 Alias = MergeAliasResults(ThisAlias, Alias);
1735 if (Alias == MayAlias)
1736 break;
1737 }
1738
1739 return Alias;
1740}
1741
1742/// Provides a bunch of ad-hoc rules to disambiguate in common cases, such as
1743/// array references.
1744AliasResult BasicAAResult::aliasCheck(const Value *V1, LocationSize V1Size,
1745 AAMDNodes V1AAInfo, const Value *V2,
1746 LocationSize V2Size, AAMDNodes V2AAInfo,
1747 AAQueryInfo &AAQI, const Value *O1,
1748 const Value *O2) {
1749 // If either of the memory references is empty, it doesn't matter what the
1750 // pointer values are.
1751 if (V1Size.isZero() || V2Size.isZero())
1752 return NoAlias;
1753
1754 // Strip off any casts if they exist.
1755 V1 = V1->stripPointerCastsAndInvariantGroups();
1756 V2 = V2->stripPointerCastsAndInvariantGroups();
1757
1758 // If V1 or V2 is undef, the result is NoAlias because we can always pick a
1759 // value for undef that aliases nothing in the program.
1760 if (isa<UndefValue>(V1) || isa<UndefValue>(V2))
1761 return NoAlias;
1762
1763 // Are we checking for alias of the same value?
1764 // Because we look 'through' phi nodes, we could look at "Value" pointers from
1765 // different iterations. We must therefore make sure that this is not the
1766 // case. The function isValueEqualInPotentialCycles ensures that this cannot
1767 // happen by looking at the visited phi nodes and making sure they cannot
1768 // reach the value.
1769 if (isValueEqualInPotentialCycles(V1, V2))
1770 return MustAlias;
1771
1772 if (!V1->getType()->isPointerTy() || !V2->getType()->isPointerTy())
1773 return NoAlias; // Scalars cannot alias each other
1774
1775 // Figure out what objects these things are pointing to if we can.
1776 if (O1 == nullptr)
1777 O1 = getUnderlyingObject(V1, MaxLookupSearchDepth);
1778
1779 if (O2 == nullptr)
1780 O2 = getUnderlyingObject(V2, MaxLookupSearchDepth);
1781
1782 // Null values in the default address space don't point to any object, so they
1783 // don't alias any other pointer.
1784 if (const ConstantPointerNull *CPN = dyn_cast<ConstantPointerNull>(O1))
1785 if (!NullPointerIsDefined(&F, CPN->getType()->getAddressSpace()))
1786 return NoAlias;
1787 if (const ConstantPointerNull *CPN = dyn_cast<ConstantPointerNull>(O2))
1788 if (!NullPointerIsDefined(&F, CPN->getType()->getAddressSpace()))
1789 return NoAlias;
1790
1791 if (O1 != O2) {
1792 // If V1/V2 point to two different objects, we know that we have no alias.
1793 if (isIdentifiedObject(O1) && isIdentifiedObject(O2))
1794 return NoAlias;
1795
1796 // Constant pointers can't alias with non-const isIdentifiedObject objects.
1797 if ((isa<Constant>(O1) && isIdentifiedObject(O2) && !isa<Constant>(O2)) ||
1798 (isa<Constant>(O2) && isIdentifiedObject(O1) && !isa<Constant>(O1)))
1799 return NoAlias;
1800
1801 // Function arguments can't alias with things that are known to be
1802 // unambigously identified at the function level.
1803 if ((isa<Argument>(O1) && isIdentifiedFunctionLocal(O2)) ||
1804 (isa<Argument>(O2) && isIdentifiedFunctionLocal(O1)))
1805 return NoAlias;
1806
1807 // If one pointer is the result of a call/invoke or load and the other is a
1808 // non-escaping local object within the same function, then we know the
1809 // object couldn't escape to a point where the call could return it.
1810 //
1811 // Note that if the pointers are in different functions, there are a
1812 // variety of complications. A call with a nocapture argument may still
1813 // temporary store the nocapture argument's value in a temporary memory
1814 // location if that memory location doesn't escape. Or it may pass a
1815 // nocapture value to other functions as long as they don't capture it.
1816 if (isEscapeSource(O1) &&
1817 isNonEscapingLocalObject(O2, &AAQI.IsCapturedCache))
1818 return NoAlias;
1819 if (isEscapeSource(O2) &&
1820 isNonEscapingLocalObject(O1, &AAQI.IsCapturedCache))
1821 return NoAlias;
1822 }
1823
1824 // If the size of one access is larger than the entire object on the other
1825 // side, then we know such behavior is undefined and can assume no alias.
1826 bool NullIsValidLocation = NullPointerIsDefined(&F);
1827 if ((isObjectSmallerThan(
1828 O2, getMinimalExtentFrom(*V1, V1Size, DL, NullIsValidLocation), DL,
1829 TLI, NullIsValidLocation)) ||
1830 (isObjectSmallerThan(
1831 O1, getMinimalExtentFrom(*V2, V2Size, DL, NullIsValidLocation), DL,
1832 TLI, NullIsValidLocation)))
1833 return NoAlias;
1834
1835 // Check the cache before climbing up use-def chains. This also terminates
1836 // otherwise infinitely recursive queries.
1837 AAQueryInfo::LocPair Locs(MemoryLocation(V1, V1Size, V1AAInfo),
1838 MemoryLocation(V2, V2Size, V2AAInfo));
1839 if (V1 > V2)
1840 std::swap(Locs.first, Locs.second);
1841 std::pair<AAQueryInfo::AliasCacheT::iterator, bool> Pair =
1842 AAQI.AliasCache.try_emplace(Locs, MayAlias);
1843 if (!Pair.second)
1844 return Pair.first->second;
1845
1846 // FIXME: This isn't aggressively handling alias(GEP, PHI) for example: if the
1847 // GEP can't simplify, we don't even look at the PHI cases.
1848 if (!isa<GEPOperator>(V1) && isa<GEPOperator>(V2)) {
1849 std::swap(V1, V2);
1850 std::swap(V1Size, V2Size);
1851 std::swap(O1, O2);
1852 std::swap(V1AAInfo, V2AAInfo);
1853 }
1854 if (const GEPOperator *GV1 = dyn_cast<GEPOperator>(V1)) {
1855 AliasResult Result =
1856 aliasGEP(GV1, V1Size, V1AAInfo, V2, V2Size, V2AAInfo, O1, O2, AAQI);
1857 if (Result != MayAlias) {
1858 auto ItInsPair = AAQI.AliasCache.insert(std::make_pair(Locs, Result));
1859 assert(!ItInsPair.second && "Entry must have existed")((!ItInsPair.second && "Entry must have existed") ? static_cast
<void> (0) : __assert_fail ("!ItInsPair.second && \"Entry must have existed\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1859, __PRETTY_FUNCTION__))
;
1860 ItInsPair.first->second = Result;
1861 return Result;
1862 }
1863 }
1864
1865 if (isa<PHINode>(V2) && !isa<PHINode>(V1)) {
1866 std::swap(V1, V2);
1867 std::swap(O1, O2);
1868 std::swap(V1Size, V2Size);
1869 std::swap(V1AAInfo, V2AAInfo);
1870 }
1871 if (const PHINode *PN = dyn_cast<PHINode>(V1)) {
1872 AliasResult Result =
1873 aliasPHI(PN, V1Size, V1AAInfo, V2, V2Size, V2AAInfo, O2, AAQI);
1874 if (Result != MayAlias) {
1875 Pair = AAQI.AliasCache.try_emplace(Locs, Result);
1876 assert(!Pair.second && "Entry must have existed")((!Pair.second && "Entry must have existed") ? static_cast
<void> (0) : __assert_fail ("!Pair.second && \"Entry must have existed\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1876, __PRETTY_FUNCTION__))
;
1877 return Pair.first->second = Result;
1878 }
1879 }
1880
1881 if (isa<SelectInst>(V2) && !isa<SelectInst>(V1)) {
1882 std::swap(V1, V2);
1883 std::swap(O1, O2);
1884 std::swap(V1Size, V2Size);
1885 std::swap(V1AAInfo, V2AAInfo);
1886 }
1887 if (const SelectInst *S1 = dyn_cast<SelectInst>(V1)) {
1888 AliasResult Result =
1889 aliasSelect(S1, V1Size, V1AAInfo, V2, V2Size, V2AAInfo, O2, AAQI);
1890 if (Result != MayAlias) {
1891 Pair = AAQI.AliasCache.try_emplace(Locs, Result);
1892 assert(!Pair.second && "Entry must have existed")((!Pair.second && "Entry must have existed") ? static_cast
<void> (0) : __assert_fail ("!Pair.second && \"Entry must have existed\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1892, __PRETTY_FUNCTION__))
;
1893 return Pair.first->second = Result;
1894 }
1895 }
1896
1897 // If both pointers are pointing into the same object and one of them
1898 // accesses the entire object, then the accesses must overlap in some way.
1899 if (O1 == O2)
1900 if (V1Size.isPrecise() && V2Size.isPrecise() &&
1901 (isObjectSize(O1, V1Size.getValue(), DL, TLI, NullIsValidLocation) ||
1902 isObjectSize(O2, V2Size.getValue(), DL, TLI, NullIsValidLocation))) {
1903 Pair = AAQI.AliasCache.try_emplace(Locs, PartialAlias);
1904 assert(!Pair.second && "Entry must have existed")((!Pair.second && "Entry must have existed") ? static_cast
<void> (0) : __assert_fail ("!Pair.second && \"Entry must have existed\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1904, __PRETTY_FUNCTION__))
;
1905 return Pair.first->second = PartialAlias;
1906 }
1907
1908 // Recurse back into the best AA results we have, potentially with refined
1909 // memory locations. We have already ensured that BasicAA has a MayAlias
1910 // cache result for these, so any recursion back into BasicAA won't loop.
1911 AliasResult Result = getBestAAResults().alias(Locs.first, Locs.second, AAQI);
1912 Pair = AAQI.AliasCache.try_emplace(Locs, Result);
1913 assert(!Pair.second && "Entry must have existed")((!Pair.second && "Entry must have existed") ? static_cast
<void> (0) : __assert_fail ("!Pair.second && \"Entry must have existed\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1913, __PRETTY_FUNCTION__))
;
1914 return Pair.first->second = Result;
1915}
1916
1917/// Check whether two Values can be considered equivalent.
1918///
1919/// In addition to pointer equivalence of \p V1 and \p V2 this checks whether
1920/// they can not be part of a cycle in the value graph by looking at all
1921/// visited phi nodes an making sure that the phis cannot reach the value. We
1922/// have to do this because we are looking through phi nodes (That is we say
1923/// noalias(V, phi(VA, VB)) if noalias(V, VA) and noalias(V, VB).
1924bool BasicAAResult::isValueEqualInPotentialCycles(const Value *V,
1925 const Value *V2) {
1926 if (V != V2)
1927 return false;
1928
1929 const Instruction *Inst = dyn_cast<Instruction>(V);
1930 if (!Inst)
1931 return true;
1932
1933 if (VisitedPhiBBs.empty())
1934 return true;
1935
1936 if (VisitedPhiBBs.size() > MaxNumPhiBBsValueReachabilityCheck)
1937 return false;
1938
1939 // Make sure that the visited phis cannot reach the Value. This ensures that
1940 // the Values cannot come from different iterations of a potential cycle the
1941 // phi nodes could be involved in.
1942 for (auto *P : VisitedPhiBBs)
1943 if (isPotentiallyReachable(&P->front(), Inst, nullptr, DT, LI))
1944 return false;
1945
1946 return true;
1947}
1948
1949/// Computes the symbolic difference between two de-composed GEPs.
1950///
1951/// Dest and Src are the variable indices from two decomposed GetElementPtr
1952/// instructions GEP1 and GEP2 which have common base pointers.
1953void BasicAAResult::GetIndexDifference(
1954 SmallVectorImpl<VariableGEPIndex> &Dest,
1955 const SmallVectorImpl<VariableGEPIndex> &Src) {
1956 if (Src.empty())
1957 return;
1958
1959 for (unsigned i = 0, e = Src.size(); i != e; ++i) {
1960 const Value *V = Src[i].V;
1961 unsigned ZExtBits = Src[i].ZExtBits, SExtBits = Src[i].SExtBits;
1962 APInt Scale = Src[i].Scale;
1963
1964 // Find V in Dest. This is N^2, but pointer indices almost never have more
1965 // than a few variable indexes.
1966 for (unsigned j = 0, e = Dest.size(); j != e; ++j) {
1967 if (!isValueEqualInPotentialCycles(Dest[j].V, V) ||
1968 Dest[j].ZExtBits != ZExtBits || Dest[j].SExtBits != SExtBits)
1969 continue;
1970
1971 // If we found it, subtract off Scale V's from the entry in Dest. If it
1972 // goes to zero, remove the entry.
1973 if (Dest[j].Scale != Scale)
1974 Dest[j].Scale -= Scale;
1975 else
1976 Dest.erase(Dest.begin() + j);
1977 Scale = 0;
1978 break;
1979 }
1980
1981 // If we didn't consume this entry, add it to the end of the Dest list.
1982 if (!!Scale) {
1983 VariableGEPIndex Entry = {V, ZExtBits, SExtBits, -Scale};
1984 Dest.push_back(Entry);
1985 }
1986 }
1987}
1988
1989bool BasicAAResult::constantOffsetHeuristic(
1990 const SmallVectorImpl<VariableGEPIndex> &VarIndices,
1991 LocationSize MaybeV1Size, LocationSize MaybeV2Size, const APInt &BaseOffset,
1992 AssumptionCache *AC, DominatorTree *DT) {
1993 if (VarIndices.size() != 2 || MaybeV1Size == LocationSize::unknown() ||
1
Assuming the condition is false
2
Taking false branch
1994 MaybeV2Size == LocationSize::unknown())
1995 return false;
1996
1997 const uint64_t V1Size = MaybeV1Size.getValue();
1998 const uint64_t V2Size = MaybeV2Size.getValue();
1999
2000 const VariableGEPIndex &Var0 = VarIndices[0], &Var1 = VarIndices[1];
2001
2002 if (Var0.ZExtBits != Var1.ZExtBits || Var0.SExtBits != Var1.SExtBits ||
3
Assuming 'Var0.ZExtBits' is equal to 'Var1.ZExtBits'
4
Assuming 'Var0.SExtBits' is equal to 'Var1.SExtBits'
5
Taking false branch
2003 Var0.Scale != -Var1.Scale)
2004 return false;
2005
2006 unsigned Width = Var1.V->getType()->getIntegerBitWidth();
2007
2008 // We'll strip off the Extensions of Var0 and Var1 and do another round
2009 // of GetLinearExpression decomposition. In the example above, if Var0
2010 // is zext(%x + 1) we should get V1 == %x and V1Offset == 1.
2011
2012 APInt V0Scale(Width, 0), V0Offset(Width, 0), V1Scale(Width, 0),
2013 V1Offset(Width, 0);
2014 bool NSW = true, NUW = true;
2015 unsigned V0ZExtBits = 0, V0SExtBits = 0, V1ZExtBits = 0, V1SExtBits = 0;
2016 const Value *V0 = GetLinearExpression(Var0.V, V0Scale, V0Offset, V0ZExtBits,
6
Calling 'BasicAAResult::GetLinearExpression'
2017 V0SExtBits, DL, 0, AC, DT, NSW, NUW);
2018 NSW = true;
2019 NUW = true;
2020 const Value *V1 = GetLinearExpression(Var1.V, V1Scale, V1Offset, V1ZExtBits,
2021 V1SExtBits, DL, 0, AC, DT, NSW, NUW);
2022
2023 if (V0Scale != V1Scale || V0ZExtBits != V1ZExtBits ||
2024 V0SExtBits != V1SExtBits || !isValueEqualInPotentialCycles(V0, V1))
2025 return false;
2026
2027 // We have a hit - Var0 and Var1 only differ by a constant offset!
2028
2029 // If we've been sext'ed then zext'd the maximum difference between Var0 and
2030 // Var1 is possible to calculate, but we're just interested in the absolute
2031 // minimum difference between the two. The minimum distance may occur due to
2032 // wrapping; consider "add i3 %i, 5": if %i == 7 then 7 + 5 mod 8 == 4, and so
2033 // the minimum distance between %i and %i + 5 is 3.
2034 APInt MinDiff = V0Offset - V1Offset, Wrapped = -MinDiff;
2035 MinDiff = APIntOps::umin(MinDiff, Wrapped);
2036 APInt MinDiffBytes =
2037 MinDiff.zextOrTrunc(Var0.Scale.getBitWidth()) * Var0.Scale.abs();
2038
2039 // We can't definitely say whether GEP1 is before or after V2 due to wrapping
2040 // arithmetic (i.e. for some values of GEP1 and V2 GEP1 < V2, and for other
2041 // values GEP1 > V2). We'll therefore only declare NoAlias if both V1Size and
2042 // V2Size can fit in the MinDiffBytes gap.
2043 return MinDiffBytes.uge(V1Size + BaseOffset.abs()) &&
2044 MinDiffBytes.uge(V2Size + BaseOffset.abs());
2045}
2046
2047//===----------------------------------------------------------------------===//
2048// BasicAliasAnalysis Pass
2049//===----------------------------------------------------------------------===//
2050
2051AnalysisKey BasicAA::Key;
2052
2053BasicAAResult BasicAA::run(Function &F, FunctionAnalysisManager &AM) {
2054 return BasicAAResult(F.getParent()->getDataLayout(),
2055 F,
2056 AM.getResult<TargetLibraryAnalysis>(F),
2057 AM.getResult<AssumptionAnalysis>(F),
2058 &AM.getResult<DominatorTreeAnalysis>(F),
2059 AM.getCachedResult<LoopAnalysis>(F),
2060 AM.getCachedResult<PhiValuesAnalysis>(F));
2061}
2062
2063BasicAAWrapperPass::BasicAAWrapperPass() : FunctionPass(ID) {
2064 initializeBasicAAWrapperPassPass(*PassRegistry::getPassRegistry());
2065}
2066
2067char BasicAAWrapperPass::ID = 0;
2068
2069void BasicAAWrapperPass::anchor() {}
2070
2071INITIALIZE_PASS_BEGIN(BasicAAWrapperPass, "basic-aa",static void *initializeBasicAAWrapperPassPassOnce(PassRegistry
&Registry) {
2072 "Basic Alias Analysis (stateless AA impl)", true, true)static void *initializeBasicAAWrapperPassPassOnce(PassRegistry
&Registry) {
2073INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)initializeAssumptionCacheTrackerPass(Registry);
2074INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)initializeDominatorTreeWrapperPassPass(Registry);
2075INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)initializeTargetLibraryInfoWrapperPassPass(Registry);
2076INITIALIZE_PASS_DEPENDENCY(PhiValuesWrapperPass)initializePhiValuesWrapperPassPass(Registry);
2077INITIALIZE_PASS_END(BasicAAWrapperPass, "basic-aa",PassInfo *PI = new PassInfo( "Basic Alias Analysis (stateless AA impl)"
, "basic-aa", &BasicAAWrapperPass::ID, PassInfo::NormalCtor_t
(callDefaultCtor<BasicAAWrapperPass>), true, true); Registry
.registerPass(*PI, true); return PI; } static llvm::once_flag
InitializeBasicAAWrapperPassPassFlag; void llvm::initializeBasicAAWrapperPassPass
(PassRegistry &Registry) { llvm::call_once(InitializeBasicAAWrapperPassPassFlag
, initializeBasicAAWrapperPassPassOnce, std::ref(Registry)); }
2078 "Basic Alias Analysis (stateless AA impl)", true, true)PassInfo *PI = new PassInfo( "Basic Alias Analysis (stateless AA impl)"
, "basic-aa", &BasicAAWrapperPass::ID, PassInfo::NormalCtor_t
(callDefaultCtor<BasicAAWrapperPass>), true, true); Registry
.registerPass(*PI, true); return PI; } static llvm::once_flag
InitializeBasicAAWrapperPassPassFlag; void llvm::initializeBasicAAWrapperPassPass
(PassRegistry &Registry) { llvm::call_once(InitializeBasicAAWrapperPassPassFlag
, initializeBasicAAWrapperPassPassOnce, std::ref(Registry)); }
2079
2080FunctionPass *llvm::createBasicAAWrapperPass() {
2081 return new BasicAAWrapperPass();
2082}
2083
2084bool BasicAAWrapperPass::runOnFunction(Function &F) {
2085 auto &ACT = getAnalysis<AssumptionCacheTracker>();
2086 auto &TLIWP = getAnalysis<TargetLibraryInfoWrapperPass>();
2087 auto &DTWP = getAnalysis<DominatorTreeWrapperPass>();
2088 auto *LIWP = getAnalysisIfAvailable<LoopInfoWrapperPass>();
2089 auto *PVWP = getAnalysisIfAvailable<PhiValuesWrapperPass>();
2090
2091 Result.reset(new BasicAAResult(F.getParent()->getDataLayout(), F,
2092 TLIWP.getTLI(F), ACT.getAssumptionCache(F),
2093 &DTWP.getDomTree(),
2094 LIWP ? &LIWP->getLoopInfo() : nullptr,
2095 PVWP ? &PVWP->getResult() : nullptr));
2096
2097 return false;
2098}
2099
2100void BasicAAWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
2101 AU.setPreservesAll();
2102 AU.addRequired<AssumptionCacheTracker>();
2103 AU.addRequired<DominatorTreeWrapperPass>();
2104 AU.addRequired<TargetLibraryInfoWrapperPass>();
2105 AU.addUsedIfAvailable<PhiValuesWrapperPass>();
2106}
2107
2108BasicAAResult llvm::createLegacyPMBasicAAResult(Pass &P, Function &F) {
2109 return BasicAAResult(
2110 F.getParent()->getDataLayout(), F,
2111 P.getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F),
2112 P.getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F));
2113}

/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h

1//===-- llvm/ADT/APInt.h - For Arbitrary Precision Integer -----*- C++ -*--===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8///
9/// \file
10/// This file implements a class to represent arbitrary precision
11/// integral constant values and operations on them.
12///
13//===----------------------------------------------------------------------===//
14
15#ifndef LLVM_ADT_APINT_H
16#define LLVM_ADT_APINT_H
17
18#include "llvm/Support/Compiler.h"
19#include "llvm/Support/MathExtras.h"
20#include <cassert>
21#include <climits>
22#include <cstring>
23#include <string>
24
25namespace llvm {
26class FoldingSetNodeID;
27class StringRef;
28class hash_code;
29class raw_ostream;
30
31template <typename T> class SmallVectorImpl;
32template <typename T> class ArrayRef;
33template <typename T> class Optional;
34template <typename T> struct DenseMapInfo;
35
36class APInt;
37
38inline APInt operator-(APInt);
39
40//===----------------------------------------------------------------------===//
41// APInt Class
42//===----------------------------------------------------------------------===//
43
44/// Class for arbitrary precision integers.
45///
46/// APInt is a functional replacement for common case unsigned integer type like
47/// "unsigned", "unsigned long" or "uint64_t", but also allows non-byte-width
48/// integer sizes and large integer value types such as 3-bits, 15-bits, or more
49/// than 64-bits of precision. APInt provides a variety of arithmetic operators
50/// and methods to manipulate integer values of any bit-width. It supports both
51/// the typical integer arithmetic and comparison operations as well as bitwise
52/// manipulation.
53///
54/// The class has several invariants worth noting:
55/// * All bit, byte, and word positions are zero-based.
56/// * Once the bit width is set, it doesn't change except by the Truncate,
57/// SignExtend, or ZeroExtend operations.
58/// * All binary operators must be on APInt instances of the same bit width.
59/// Attempting to use these operators on instances with different bit
60/// widths will yield an assertion.
61/// * The value is stored canonically as an unsigned value. For operations
62/// where it makes a difference, there are both signed and unsigned variants
63/// of the operation. For example, sdiv and udiv. However, because the bit
64/// widths must be the same, operations such as Mul and Add produce the same
65/// results regardless of whether the values are interpreted as signed or
66/// not.
67/// * In general, the class tries to follow the style of computation that LLVM
68/// uses in its IR. This simplifies its use for LLVM.
69///
70class LLVM_NODISCARD[[clang::warn_unused_result]] APInt {
71public:
72 typedef uint64_t WordType;
73
74 /// This enum is used to hold the constants we needed for APInt.
75 enum : unsigned {
76 /// Byte size of a word.
77 APINT_WORD_SIZE = sizeof(WordType),
78 /// Bits in a word.
79 APINT_BITS_PER_WORD = APINT_WORD_SIZE * CHAR_BIT8
80 };
81
82 enum class Rounding {
83 DOWN,
84 TOWARD_ZERO,
85 UP,
86 };
87
88 static constexpr WordType WORDTYPE_MAX = ~WordType(0);
89
90private:
91 /// This union is used to store the integer value. When the
92 /// integer bit-width <= 64, it uses VAL, otherwise it uses pVal.
93 union {
94 uint64_t VAL; ///< Used to store the <= 64 bits integer value.
95 uint64_t *pVal; ///< Used to store the >64 bits integer value.
96 } U;
97
98 unsigned BitWidth; ///< The number of bits in this APInt.
99
100 friend struct DenseMapInfo<APInt>;
101
102 friend class APSInt;
103
104 /// Fast internal constructor
105 ///
106 /// This constructor is used only internally for speed of construction of
107 /// temporaries. It is unsafe for general use so it is not public.
108 APInt(uint64_t *val, unsigned bits) : BitWidth(bits) {
109 U.pVal = val;
110 }
111
112 /// Determine if this APInt just has one word to store value.
113 ///
114 /// \returns true if the number of bits <= 64, false otherwise.
115 bool isSingleWord() const { return BitWidth <= APINT_BITS_PER_WORD; }
116
117 /// Determine which word a bit is in.
118 ///
119 /// \returns the word position for the specified bit position.
120 static unsigned whichWord(unsigned bitPosition) {
121 return bitPosition / APINT_BITS_PER_WORD;
122 }
123
124 /// Determine which bit in a word a bit is in.
125 ///
126 /// \returns the bit position in a word for the specified bit position
127 /// in the APInt.
128 static unsigned whichBit(unsigned bitPosition) {
129 return bitPosition % APINT_BITS_PER_WORD;
130 }
131
132 /// Get a single bit mask.
133 ///
134 /// \returns a uint64_t with only bit at "whichBit(bitPosition)" set
135 /// This method generates and returns a uint64_t (word) mask for a single
136 /// bit at a specific bit position. This is used to mask the bit in the
137 /// corresponding word.
138 static uint64_t maskBit(unsigned bitPosition) {
139 return 1ULL << whichBit(bitPosition);
140 }
141
142 /// Clear unused high order bits
143 ///
144 /// This method is used internally to clear the top "N" bits in the high order
145 /// word that are not used by the APInt. This is needed after the most
146 /// significant word is assigned a value to ensure that those bits are
147 /// zero'd out.
148 APInt &clearUnusedBits() {
149 // Compute how many bits are used in the final word
150 unsigned WordBits = ((BitWidth-1) % APINT_BITS_PER_WORD) + 1;
151
152 // Mask out the high bits.
153 uint64_t mask = WORDTYPE_MAX >> (APINT_BITS_PER_WORD - WordBits);
154 if (isSingleWord())
155 U.VAL &= mask;
156 else
157 U.pVal[getNumWords() - 1] &= mask;
158 return *this;
159 }
160
161 /// Get the word corresponding to a bit position
162 /// \returns the corresponding word for the specified bit position.
163 uint64_t getWord(unsigned bitPosition) const {
164 return isSingleWord() ? U.VAL : U.pVal[whichWord(bitPosition)];
165 }
166
167 /// Utility method to change the bit width of this APInt to new bit width,
168 /// allocating and/or deallocating as necessary. There is no guarantee on the
169 /// value of any bits upon return. Caller should populate the bits after.
170 void reallocate(unsigned NewBitWidth);
171
172 /// Convert a char array into an APInt
173 ///
174 /// \param radix 2, 8, 10, 16, or 36
175 /// Converts a string into a number. The string must be non-empty
176 /// and well-formed as a number of the given base. The bit-width
177 /// must be sufficient to hold the result.
178 ///
179 /// This is used by the constructors that take string arguments.
180 ///
181 /// StringRef::getAsInteger is superficially similar but (1) does
182 /// not assume that the string is well-formed and (2) grows the
183 /// result to hold the input.
184 void fromString(unsigned numBits, StringRef str, uint8_t radix);
185
186 /// An internal division function for dividing APInts.
187 ///
188 /// This is used by the toString method to divide by the radix. It simply
189 /// provides a more convenient form of divide for internal use since KnuthDiv
190 /// has specific constraints on its inputs. If those constraints are not met
191 /// then it provides a simpler form of divide.
192 static void divide(const WordType *LHS, unsigned lhsWords,
193 const WordType *RHS, unsigned rhsWords, WordType *Quotient,
194 WordType *Remainder);
195
196 /// out-of-line slow case for inline constructor
197 void initSlowCase(uint64_t val, bool isSigned);
198
199 /// shared code between two array constructors
200 void initFromArray(ArrayRef<uint64_t> array);
201
202 /// out-of-line slow case for inline copy constructor
203 void initSlowCase(const APInt &that);
204
205 /// out-of-line slow case for shl
206 void shlSlowCase(unsigned ShiftAmt);
207
208 /// out-of-line slow case for lshr.
209 void lshrSlowCase(unsigned ShiftAmt);
210
211 /// out-of-line slow case for ashr.
212 void ashrSlowCase(unsigned ShiftAmt);
213
214 /// out-of-line slow case for operator=
215 void AssignSlowCase(const APInt &RHS);
216
217 /// out-of-line slow case for operator==
218 bool EqualSlowCase(const APInt &RHS) const LLVM_READONLY__attribute__((__pure__));
219
220 /// out-of-line slow case for countLeadingZeros
221 unsigned countLeadingZerosSlowCase() const LLVM_READONLY__attribute__((__pure__));
222
223 /// out-of-line slow case for countLeadingOnes.
224 unsigned countLeadingOnesSlowCase() const LLVM_READONLY__attribute__((__pure__));
225
226 /// out-of-line slow case for countTrailingZeros.
227 unsigned countTrailingZerosSlowCase() const LLVM_READONLY__attribute__((__pure__));
228
229 /// out-of-line slow case for countTrailingOnes
230 unsigned countTrailingOnesSlowCase() const LLVM_READONLY__attribute__((__pure__));
231
232 /// out-of-line slow case for countPopulation
233 unsigned countPopulationSlowCase() const LLVM_READONLY__attribute__((__pure__));
234
235 /// out-of-line slow case for intersects.
236 bool intersectsSlowCase(const APInt &RHS) const LLVM_READONLY__attribute__((__pure__));
237
238 /// out-of-line slow case for isSubsetOf.
239 bool isSubsetOfSlowCase(const APInt &RHS) const LLVM_READONLY__attribute__((__pure__));
240
241 /// out-of-line slow case for setBits.
242 void setBitsSlowCase(unsigned loBit, unsigned hiBit);
243
244 /// out-of-line slow case for flipAllBits.
245 void flipAllBitsSlowCase();
246
247 /// out-of-line slow case for operator&=.
248 void AndAssignSlowCase(const APInt& RHS);
249
250 /// out-of-line slow case for operator|=.
251 void OrAssignSlowCase(const APInt& RHS);
252
253 /// out-of-line slow case for operator^=.
254 void XorAssignSlowCase(const APInt& RHS);
255
256 /// Unsigned comparison. Returns -1, 0, or 1 if this APInt is less than, equal
257 /// to, or greater than RHS.
258 int compare(const APInt &RHS) const LLVM_READONLY__attribute__((__pure__));
259
260 /// Signed comparison. Returns -1, 0, or 1 if this APInt is less than, equal
261 /// to, or greater than RHS.
262 int compareSigned(const APInt &RHS) const LLVM_READONLY__attribute__((__pure__));
263
264public:
265 /// \name Constructors
266 /// @{
267
268 /// Create a new APInt of numBits width, initialized as val.
269 ///
270 /// If isSigned is true then val is treated as if it were a signed value
271 /// (i.e. as an int64_t) and the appropriate sign extension to the bit width
272 /// will be done. Otherwise, no sign extension occurs (high order bits beyond
273 /// the range of val are zero filled).
274 ///
275 /// \param numBits the bit width of the constructed APInt
276 /// \param val the initial value of the APInt
277 /// \param isSigned how to treat signedness of val
278 APInt(unsigned numBits, uint64_t val, bool isSigned = false)
279 : BitWidth(numBits) {
280 assert(BitWidth && "bitwidth too small")((BitWidth && "bitwidth too small") ? static_cast<
void> (0) : __assert_fail ("BitWidth && \"bitwidth too small\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 280, __PRETTY_FUNCTION__))
;
281 if (isSingleWord()) {
282 U.VAL = val;
283 clearUnusedBits();
284 } else {
285 initSlowCase(val, isSigned);
286 }
287 }
288
289 /// Construct an APInt of numBits width, initialized as bigVal[].
290 ///
291 /// Note that bigVal.size() can be smaller or larger than the corresponding
292 /// bit width but any extraneous bits will be dropped.
293 ///
294 /// \param numBits the bit width of the constructed APInt
295 /// \param bigVal a sequence of words to form the initial value of the APInt
296 APInt(unsigned numBits, ArrayRef<uint64_t> bigVal);
297
298 /// Equivalent to APInt(numBits, ArrayRef<uint64_t>(bigVal, numWords)), but
299 /// deprecated because this constructor is prone to ambiguity with the
300 /// APInt(unsigned, uint64_t, bool) constructor.
301 ///
302 /// If this overload is ever deleted, care should be taken to prevent calls
303 /// from being incorrectly captured by the APInt(unsigned, uint64_t, bool)
304 /// constructor.
305 APInt(unsigned numBits, unsigned numWords, const uint64_t bigVal[]);
306
307 /// Construct an APInt from a string representation.
308 ///
309 /// This constructor interprets the string \p str in the given radix. The
310 /// interpretation stops when the first character that is not suitable for the
311 /// radix is encountered, or the end of the string. Acceptable radix values
312 /// are 2, 8, 10, 16, and 36. It is an error for the value implied by the
313 /// string to require more bits than numBits.
314 ///
315 /// \param numBits the bit width of the constructed APInt
316 /// \param str the string to be interpreted
317 /// \param radix the radix to use for the conversion
318 APInt(unsigned numBits, StringRef str, uint8_t radix);
319
320 /// Simply makes *this a copy of that.
321 /// Copy Constructor.
322 APInt(const APInt &that) : BitWidth(that.BitWidth) {
323 if (isSingleWord())
324 U.VAL = that.U.VAL;
325 else
326 initSlowCase(that);
327 }
328
329 /// Move Constructor.
330 APInt(APInt &&that) : BitWidth(that.BitWidth) {
331 memcpy(&U, &that.U, sizeof(U));
332 that.BitWidth = 0;
333 }
334
335 /// Destructor.
336 ~APInt() {
337 if (needsCleanup())
338 delete[] U.pVal;
339 }
340
341 /// Default constructor that creates an uninteresting APInt
342 /// representing a 1-bit zero value.
343 ///
344 /// This is useful for object deserialization (pair this with the static
345 /// method Read).
346 explicit APInt() : BitWidth(1) { U.VAL = 0; }
347
348 /// Returns whether this instance allocated memory.
349 bool needsCleanup() const { return !isSingleWord(); }
350
351 /// Used to insert APInt objects, or objects that contain APInt objects, into
352 /// FoldingSets.
353 void Profile(FoldingSetNodeID &id) const;
354
355 /// @}
356 /// \name Value Tests
357 /// @{
358
359 /// Determine sign of this APInt.
360 ///
361 /// This tests the high bit of this APInt to determine if it is set.
362 ///
363 /// \returns true if this APInt is negative, false otherwise
364 bool isNegative() const { return (*this)[BitWidth - 1]; }
365
366 /// Determine if this APInt Value is non-negative (>= 0)
367 ///
368 /// This tests the high bit of the APInt to determine if it is unset.
369 bool isNonNegative() const { return !isNegative(); }
370
371 /// Determine if sign bit of this APInt is set.
372 ///
373 /// This tests the high bit of this APInt to determine if it is set.
374 ///
375 /// \returns true if this APInt has its sign bit set, false otherwise.
376 bool isSignBitSet() const { return (*this)[BitWidth-1]; }
377
378 /// Determine if sign bit of this APInt is clear.
379 ///
380 /// This tests the high bit of this APInt to determine if it is clear.
381 ///
382 /// \returns true if this APInt has its sign bit clear, false otherwise.
383 bool isSignBitClear() const { return !isSignBitSet(); }
384
385 /// Determine if this APInt Value is positive.
386 ///
387 /// This tests if the value of this APInt is positive (> 0). Note
388 /// that 0 is not a positive value.
389 ///
390 /// \returns true if this APInt is positive.
391 bool isStrictlyPositive() const { return isNonNegative() && !isNullValue(); }
392
393 /// Determine if this APInt Value is non-positive (<= 0).
394 ///
395 /// \returns true if this APInt is non-positive.
396 bool isNonPositive() const { return !isStrictlyPositive(); }
397
398 /// Determine if all bits are set
399 ///
400 /// This checks to see if the value has all bits of the APInt are set or not.
401 bool isAllOnesValue() const {
402 if (isSingleWord())
403 return U.VAL == WORDTYPE_MAX >> (APINT_BITS_PER_WORD - BitWidth);
404 return countTrailingOnesSlowCase() == BitWidth;
405 }
406
407 /// Determine if all bits are clear
408 ///
409 /// This checks to see if the value has all bits of the APInt are clear or
410 /// not.
411 bool isNullValue() const { return !*this; }
412
413 /// Determine if this is a value of 1.
414 ///
415 /// This checks to see if the value of this APInt is one.
416 bool isOneValue() const {
417 if (isSingleWord())
418 return U.VAL == 1;
419 return countLeadingZerosSlowCase() == BitWidth - 1;
420 }
421
422 /// Determine if this is the largest unsigned value.
423 ///
424 /// This checks to see if the value of this APInt is the maximum unsigned
425 /// value for the APInt's bit width.
426 bool isMaxValue() const { return isAllOnesValue(); }
427
428 /// Determine if this is the largest signed value.
429 ///
430 /// This checks to see if the value of this APInt is the maximum signed
431 /// value for the APInt's bit width.
432 bool isMaxSignedValue() const {
433 if (isSingleWord())
434 return U.VAL == ((WordType(1) << (BitWidth - 1)) - 1);
435 return !isNegative() && countTrailingOnesSlowCase() == BitWidth - 1;
436 }
437
438 /// Determine if this is the smallest unsigned value.
439 ///
440 /// This checks to see if the value of this APInt is the minimum unsigned
441 /// value for the APInt's bit width.
442 bool isMinValue() const { return isNullValue(); }
443
444 /// Determine if this is the smallest signed value.
445 ///
446 /// This checks to see if the value of this APInt is the minimum signed
447 /// value for the APInt's bit width.
448 bool isMinSignedValue() const {
449 if (isSingleWord())
450 return U.VAL == (WordType(1) << (BitWidth - 1));
451 return isNegative() && countTrailingZerosSlowCase() == BitWidth - 1;
452 }
453
454 /// Check if this APInt has an N-bits unsigned integer value.
455 bool isIntN(unsigned N) const {
456 assert(N && "N == 0 ???")((N && "N == 0 ???") ? static_cast<void> (0) : __assert_fail
("N && \"N == 0 ???\"", "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 456, __PRETTY_FUNCTION__))
;
457 return getActiveBits() <= N;
458 }
459
460 /// Check if this APInt has an N-bits signed integer value.
461 bool isSignedIntN(unsigned N) const {
462 assert(N && "N == 0 ???")((N && "N == 0 ???") ? static_cast<void> (0) : __assert_fail
("N && \"N == 0 ???\"", "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 462, __PRETTY_FUNCTION__))
;
463 return getMinSignedBits() <= N;
464 }
465
466 /// Check if this APInt's value is a power of two greater than zero.
467 ///
468 /// \returns true if the argument APInt value is a power of two > 0.
469 bool isPowerOf2() const {
470 if (isSingleWord())
471 return isPowerOf2_64(U.VAL);
472 return countPopulationSlowCase() == 1;
473 }
474
475 /// Check if the APInt's value is returned by getSignMask.
476 ///
477 /// \returns true if this is the value returned by getSignMask.
478 bool isSignMask() const { return isMinSignedValue(); }
479
480 /// Convert APInt to a boolean value.
481 ///
482 /// This converts the APInt to a boolean value as a test against zero.
483 bool getBoolValue() const { return !!*this; }
484
485 /// If this value is smaller than the specified limit, return it, otherwise
486 /// return the limit value. This causes the value to saturate to the limit.
487 uint64_t getLimitedValue(uint64_t Limit = UINT64_MAX(18446744073709551615UL)) const {
488 return ugt(Limit) ? Limit : getZExtValue();
21
'?' condition is true
22
Returning the value 18446744073709551615
489 }
490
491 /// Check if the APInt consists of a repeated bit pattern.
492 ///
493 /// e.g. 0x01010101 satisfies isSplat(8).
494 /// \param SplatSizeInBits The size of the pattern in bits. Must divide bit
495 /// width without remainder.
496 bool isSplat(unsigned SplatSizeInBits) const;
497
498 /// \returns true if this APInt value is a sequence of \param numBits ones
499 /// starting at the least significant bit with the remainder zero.
500 bool isMask(unsigned numBits) const {
501 assert(numBits != 0 && "numBits must be non-zero")((numBits != 0 && "numBits must be non-zero") ? static_cast
<void> (0) : __assert_fail ("numBits != 0 && \"numBits must be non-zero\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 501, __PRETTY_FUNCTION__))
;
502 assert(numBits <= BitWidth && "numBits out of range")((numBits <= BitWidth && "numBits out of range") ?
static_cast<void> (0) : __assert_fail ("numBits <= BitWidth && \"numBits out of range\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 502, __PRETTY_FUNCTION__))
;
503 if (isSingleWord())
504 return U.VAL == (WORDTYPE_MAX >> (APINT_BITS_PER_WORD - numBits));
505 unsigned Ones = countTrailingOnesSlowCase();
506 return (numBits == Ones) &&
507 ((Ones + countLeadingZerosSlowCase()) == BitWidth);
508 }
509
510 /// \returns true if this APInt is a non-empty sequence of ones starting at
511 /// the least significant bit with the remainder zero.
512 /// Ex. isMask(0x0000FFFFU) == true.
513 bool isMask() const {
514 if (isSingleWord())
515 return isMask_64(U.VAL);
516 unsigned Ones = countTrailingOnesSlowCase();
517 return (Ones > 0) && ((Ones + countLeadingZerosSlowCase()) == BitWidth);
518 }
519
520 /// Return true if this APInt value contains a sequence of ones with
521 /// the remainder zero.
522 bool isShiftedMask() const {
523 if (isSingleWord())
524 return isShiftedMask_64(U.VAL);
525 unsigned Ones = countPopulationSlowCase();
526 unsigned LeadZ = countLeadingZerosSlowCase();
527 return (Ones + LeadZ + countTrailingZeros()) == BitWidth;
528 }
529
530 /// @}
531 /// \name Value Generators
532 /// @{
533
534 /// Gets maximum unsigned value of APInt for specific bit width.
535 static APInt getMaxValue(unsigned numBits) {
536 return getAllOnesValue(numBits);
537 }
538
539 /// Gets maximum signed value of APInt for a specific bit width.
540 static APInt getSignedMaxValue(unsigned numBits) {
541 APInt API = getAllOnesValue(numBits);
542 API.clearBit(numBits - 1);
543 return API;
544 }
545
546 /// Gets minimum unsigned value of APInt for a specific bit width.
547 static APInt getMinValue(unsigned numBits) { return APInt(numBits, 0); }
548
549 /// Gets minimum signed value of APInt for a specific bit width.
550 static APInt getSignedMinValue(unsigned numBits) {
551 APInt API(numBits, 0);
552 API.setBit(numBits - 1);
553 return API;
554 }
555
556 /// Get the SignMask for a specific bit width.
557 ///
558 /// This is just a wrapper function of getSignedMinValue(), and it helps code
559 /// readability when we want to get a SignMask.
560 static APInt getSignMask(unsigned BitWidth) {
561 return getSignedMinValue(BitWidth);
562 }
563
564 /// Get the all-ones value.
565 ///
566 /// \returns the all-ones value for an APInt of the specified bit-width.
567 static APInt getAllOnesValue(unsigned numBits) {
568 return APInt(numBits, WORDTYPE_MAX, true);
569 }
570
571 /// Get the '0' value.
572 ///
573 /// \returns the '0' value for an APInt of the specified bit-width.
574 static APInt getNullValue(unsigned numBits) { return APInt(numBits, 0); }
575
576 /// Compute an APInt containing numBits highbits from this APInt.
577 ///
578 /// Get an APInt with the same BitWidth as this APInt, just zero mask
579 /// the low bits and right shift to the least significant bit.
580 ///
581 /// \returns the high "numBits" bits of this APInt.
582 APInt getHiBits(unsigned numBits) const;
583
584 /// Compute an APInt containing numBits lowbits from this APInt.
585 ///
586 /// Get an APInt with the same BitWidth as this APInt, just zero mask
587 /// the high bits.
588 ///
589 /// \returns the low "numBits" bits of this APInt.
590 APInt getLoBits(unsigned numBits) const;
591
592 /// Return an APInt with exactly one bit set in the result.
593 static APInt getOneBitSet(unsigned numBits, unsigned BitNo) {
594 APInt Res(numBits, 0);
595 Res.setBit(BitNo);
596 return Res;
597 }
598
599 /// Get a value with a block of bits set.
600 ///
601 /// Constructs an APInt value that has a contiguous range of bits set. The
602 /// bits from loBit (inclusive) to hiBit (exclusive) will be set. All other
603 /// bits will be zero. For example, with parameters(32, 0, 16) you would get
604 /// 0x0000FFFF. Please call getBitsSetWithWrap if \p loBit may be greater than
605 /// \p hiBit.
606 ///
607 /// \param numBits the intended bit width of the result
608 /// \param loBit the index of the lowest bit set.
609 /// \param hiBit the index of the highest bit set.
610 ///
611 /// \returns An APInt value with the requested bits set.
612 static APInt getBitsSet(unsigned numBits, unsigned loBit, unsigned hiBit) {
613 assert(loBit <= hiBit && "loBit greater than hiBit")((loBit <= hiBit && "loBit greater than hiBit") ? static_cast
<void> (0) : __assert_fail ("loBit <= hiBit && \"loBit greater than hiBit\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 613, __PRETTY_FUNCTION__))
;
614 APInt Res(numBits, 0);
615 Res.setBits(loBit, hiBit);
616 return Res;
617 }
618
619 /// Wrap version of getBitsSet.
620 /// If \p hiBit is bigger than \p loBit, this is same with getBitsSet.
621 /// If \p hiBit is not bigger than \p loBit, the set bits "wrap". For example,
622 /// with parameters (32, 28, 4), you would get 0xF000000F.
623 /// If \p hiBit is equal to \p loBit, you would get a result with all bits
624 /// set.
625 static APInt getBitsSetWithWrap(unsigned numBits, unsigned loBit,
626 unsigned hiBit) {
627 APInt Res(numBits, 0);
628 Res.setBitsWithWrap(loBit, hiBit);
629 return Res;
630 }
631
632 /// Get a value with upper bits starting at loBit set.
633 ///
634 /// Constructs an APInt value that has a contiguous range of bits set. The
635 /// bits from loBit (inclusive) to numBits (exclusive) will be set. All other
636 /// bits will be zero. For example, with parameters(32, 12) you would get
637 /// 0xFFFFF000.
638 ///
639 /// \param numBits the intended bit width of the result
640 /// \param loBit the index of the lowest bit to set.
641 ///
642 /// \returns An APInt value with the requested bits set.
643 static APInt getBitsSetFrom(unsigned numBits, unsigned loBit) {
644 APInt Res(numBits, 0);
645 Res.setBitsFrom(loBit);
646 return Res;
647 }
648
649 /// Get a value with high bits set
650 ///
651 /// Constructs an APInt value that has the top hiBitsSet bits set.
652 ///
653 /// \param numBits the bitwidth of the result
654 /// \param hiBitsSet the number of high-order bits set in the result.
655 static APInt getHighBitsSet(unsigned numBits, unsigned hiBitsSet) {
656 APInt Res(numBits, 0);
657 Res.setHighBits(hiBitsSet);
658 return Res;
659 }
660
661 /// Get a value with low bits set
662 ///
663 /// Constructs an APInt value that has the bottom loBitsSet bits set.
664 ///
665 /// \param numBits the bitwidth of the result
666 /// \param loBitsSet the number of low-order bits set in the result.
667 static APInt getLowBitsSet(unsigned numBits, unsigned loBitsSet) {
668 APInt Res(numBits, 0);
669 Res.setLowBits(loBitsSet);
670 return Res;
671 }
672
673 /// Return a value containing V broadcasted over NewLen bits.
674 static APInt getSplat(unsigned NewLen, const APInt &V);
675
676 /// Determine if two APInts have the same value, after zero-extending
677 /// one of them (if needed!) to ensure that the bit-widths match.
678 static bool isSameValue(const APInt &I1, const APInt &I2) {
679 if (I1.getBitWidth() == I2.getBitWidth())
680 return I1 == I2;
681
682 if (I1.getBitWidth() > I2.getBitWidth())
683 return I1 == I2.zext(I1.getBitWidth());
684
685 return I1.zext(I2.getBitWidth()) == I2;
686 }
687
688 /// Overload to compute a hash_code for an APInt value.
689 friend hash_code hash_value(const APInt &Arg);
690
691 /// This function returns a pointer to the internal storage of the APInt.
692 /// This is useful for writing out the APInt in binary form without any
693 /// conversions.
694 const uint64_t *getRawData() const {
695 if (isSingleWord())
696 return &U.VAL;
697 return &U.pVal[0];
698 }
699
700 /// @}
701 /// \name Unary Operators
702 /// @{
703
704 /// Postfix increment operator.
705 ///
706 /// Increments *this by 1.
707 ///
708 /// \returns a new APInt value representing the original value of *this.
709 const APInt operator++(int) {
710 APInt API(*this);
711 ++(*this);
712 return API;
713 }
714
715 /// Prefix increment operator.
716 ///
717 /// \returns *this incremented by one
718 APInt &operator++();
719
720 /// Postfix decrement operator.
721 ///
722 /// Decrements *this by 1.
723 ///
724 /// \returns a new APInt value representing the original value of *this.
725 const APInt operator--(int) {
726 APInt API(*this);
727 --(*this);
728 return API;
729 }
730
731 /// Prefix decrement operator.
732 ///
733 /// \returns *this decremented by one.
734 APInt &operator--();
735
736 /// Logical negation operator.
737 ///
738 /// Performs logical negation operation on this APInt.
739 ///
740 /// \returns true if *this is zero, false otherwise.
741 bool operator!() const {
742 if (isSingleWord())
743 return U.VAL == 0;
744 return countLeadingZerosSlowCase() == BitWidth;
745 }
746
747 /// @}
748 /// \name Assignment Operators
749 /// @{
750
751 /// Copy assignment operator.
752 ///
753 /// \returns *this after assignment of RHS.
754 APInt &operator=(const APInt &RHS) {
755 // If the bitwidths are the same, we can avoid mucking with memory
756 if (isSingleWord() && RHS.isSingleWord()) {
757 U.VAL = RHS.U.VAL;
758 BitWidth = RHS.BitWidth;
759 return clearUnusedBits();
760 }
761
762 AssignSlowCase(RHS);
763 return *this;
764 }
765
766 /// Move assignment operator.
767 APInt &operator=(APInt &&that) {
768#ifdef EXPENSIVE_CHECKS
769 // Some std::shuffle implementations still do self-assignment.
770 if (this == &that)
771 return *this;
772#endif
773 assert(this != &that && "Self-move not supported")((this != &that && "Self-move not supported") ? static_cast
<void> (0) : __assert_fail ("this != &that && \"Self-move not supported\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 773, __PRETTY_FUNCTION__))
;
774 if (!isSingleWord())
775 delete[] U.pVal;
776
777 // Use memcpy so that type based alias analysis sees both VAL and pVal
778 // as modified.
779 memcpy(&U, &that.U, sizeof(U));
780
781 BitWidth = that.BitWidth;
782 that.BitWidth = 0;
783
784 return *this;
785 }
786
787 /// Assignment operator.
788 ///
789 /// The RHS value is assigned to *this. If the significant bits in RHS exceed
790 /// the bit width, the excess bits are truncated. If the bit width is larger
791 /// than 64, the value is zero filled in the unspecified high order bits.
792 ///
793 /// \returns *this after assignment of RHS value.
794 APInt &operator=(uint64_t RHS) {
795 if (isSingleWord()) {
796 U.VAL = RHS;
797 return clearUnusedBits();
798 }
799 U.pVal[0] = RHS;
800 memset(U.pVal + 1, 0, (getNumWords() - 1) * APINT_WORD_SIZE);
801 return *this;
802 }
803
804 /// Bitwise AND assignment operator.
805 ///
806 /// Performs a bitwise AND operation on this APInt and RHS. The result is
807 /// assigned to *this.
808 ///
809 /// \returns *this after ANDing with RHS.
810 APInt &operator&=(const APInt &RHS) {
811 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same")((BitWidth == RHS.BitWidth && "Bit widths must be the same"
) ? static_cast<void> (0) : __assert_fail ("BitWidth == RHS.BitWidth && \"Bit widths must be the same\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 811, __PRETTY_FUNCTION__))
;
812 if (isSingleWord())
813 U.VAL &= RHS.U.VAL;
814 else
815 AndAssignSlowCase(RHS);
816 return *this;
817 }
818
819 /// Bitwise AND assignment operator.
820 ///
821 /// Performs a bitwise AND operation on this APInt and RHS. RHS is
822 /// logically zero-extended or truncated to match the bit-width of
823 /// the LHS.
824 APInt &operator&=(uint64_t RHS) {
825 if (isSingleWord()) {
826 U.VAL &= RHS;
827 return *this;
828 }
829 U.pVal[0] &= RHS;
830 memset(U.pVal+1, 0, (getNumWords() - 1) * APINT_WORD_SIZE);
831 return *this;
832 }
833
834 /// Bitwise OR assignment operator.
835 ///
836 /// Performs a bitwise OR operation on this APInt and RHS. The result is
837 /// assigned *this;
838 ///
839 /// \returns *this after ORing with RHS.
840 APInt &operator|=(const APInt &RHS) {
841 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same")((BitWidth == RHS.BitWidth && "Bit widths must be the same"
) ? static_cast<void> (0) : __assert_fail ("BitWidth == RHS.BitWidth && \"Bit widths must be the same\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 841, __PRETTY_FUNCTION__))
;
842 if (isSingleWord())
843 U.VAL |= RHS.U.VAL;
844 else
845 OrAssignSlowCase(RHS);
846 return *this;
847 }
848
849 /// Bitwise OR assignment operator.
850 ///
851 /// Performs a bitwise OR operation on this APInt and RHS. RHS is
852 /// logically zero-extended or truncated to match the bit-width of
853 /// the LHS.
854 APInt &operator|=(uint64_t RHS) {
855 if (isSingleWord()) {
856 U.VAL |= RHS;
857 return clearUnusedBits();
858 }
859 U.pVal[0] |= RHS;
860 return *this;
861 }
862
863 /// Bitwise XOR assignment operator.
864 ///
865 /// Performs a bitwise XOR operation on this APInt and RHS. The result is
866 /// assigned to *this.
867 ///
868 /// \returns *this after XORing with RHS.
869 APInt &operator^=(const APInt &RHS) {
870 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same")((BitWidth == RHS.BitWidth && "Bit widths must be the same"
) ? static_cast<void> (0) : __assert_fail ("BitWidth == RHS.BitWidth && \"Bit widths must be the same\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 870, __PRETTY_FUNCTION__))
;
871 if (isSingleWord())
872 U.VAL ^= RHS.U.VAL;
873 else
874 XorAssignSlowCase(RHS);
875 return *this;
876 }
877
878 /// Bitwise XOR assignment operator.
879 ///
880 /// Performs a bitwise XOR operation on this APInt and RHS. RHS is
881 /// logically zero-extended or truncated to match the bit-width of
882 /// the LHS.
883 APInt &operator^=(uint64_t RHS) {
884 if (isSingleWord()) {
885 U.VAL ^= RHS;
886 return clearUnusedBits();
887 }
888 U.pVal[0] ^= RHS;
889 return *this;
890 }
891
892 /// Multiplication assignment operator.
893 ///
894 /// Multiplies this APInt by RHS and assigns the result to *this.
895 ///
896 /// \returns *this
897 APInt &operator*=(const APInt &RHS);
898 APInt &operator*=(uint64_t RHS);
899
900 /// Addition assignment operator.
901 ///
902 /// Adds RHS to *this and assigns the result to *this.
903 ///
904 /// \returns *this
905 APInt &operator+=(const APInt &RHS);
906 APInt &operator+=(uint64_t RHS);
907
908 /// Subtraction assignment operator.
909 ///
910 /// Subtracts RHS from *this and assigns the result to *this.
911 ///
912 /// \returns *this
913 APInt &operator-=(const APInt &RHS);
914 APInt &operator-=(uint64_t RHS);
915
916 /// Left-shift assignment function.
917 ///
918 /// Shifts *this left by shiftAmt and assigns the result to *this.
919 ///
920 /// \returns *this after shifting left by ShiftAmt
921 APInt &operator<<=(unsigned ShiftAmt) {
922 assert(ShiftAmt <= BitWidth && "Invalid shift amount")((ShiftAmt <= BitWidth && "Invalid shift amount") ?
static_cast<void> (0) : __assert_fail ("ShiftAmt <= BitWidth && \"Invalid shift amount\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 922, __PRETTY_FUNCTION__))
;
26
Assuming 'ShiftAmt' is <= field 'BitWidth'
27
'?' condition is true
923 if (isSingleWord()) {
28
Assuming the condition is true
29
Taking true branch
924 if (ShiftAmt == BitWidth)
30
Assuming 'ShiftAmt' is not equal to field 'BitWidth'
31
Taking false branch
925 U.VAL = 0;
926 else
927 U.VAL <<= ShiftAmt;
32
Assigned value is garbage or undefined
928 return clearUnusedBits();
929 }
930 shlSlowCase(ShiftAmt);
931 return *this;
932 }
933
934 /// Left-shift assignment function.
935 ///
936 /// Shifts *this left by shiftAmt and assigns the result to *this.
937 ///
938 /// \returns *this after shifting left by ShiftAmt
939 APInt &operator<<=(const APInt &ShiftAmt);
940
941 /// @}
942 /// \name Binary Operators
943 /// @{
944
945 /// Multiplication operator.
946 ///
947 /// Multiplies this APInt by RHS and returns the result.
948 APInt operator*(const APInt &RHS) const;
949
950 /// Left logical shift operator.
951 ///
952 /// Shifts this APInt left by \p Bits and returns the result.
953 APInt operator<<(unsigned Bits) const { return shl(Bits); }
954
955 /// Left logical shift operator.
956 ///
957 /// Shifts this APInt left by \p Bits and returns the result.
958 APInt operator<<(const APInt &Bits) const { return shl(Bits); }
959
960 /// Arithmetic right-shift function.
961 ///
962 /// Arithmetic right-shift this APInt by shiftAmt.
963 APInt ashr(unsigned ShiftAmt) const {
964 APInt R(*this);
965 R.ashrInPlace(ShiftAmt);
966 return R;
967 }
968
969 /// Arithmetic right-shift this APInt by ShiftAmt in place.
970 void ashrInPlace(unsigned ShiftAmt) {
971 assert(ShiftAmt <= BitWidth && "Invalid shift amount")((ShiftAmt <= BitWidth && "Invalid shift amount") ?
static_cast<void> (0) : __assert_fail ("ShiftAmt <= BitWidth && \"Invalid shift amount\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 971, __PRETTY_FUNCTION__))
;
972 if (isSingleWord()) {
973 int64_t SExtVAL = SignExtend64(U.VAL, BitWidth);
974 if (ShiftAmt == BitWidth)
975 U.VAL = SExtVAL >> (APINT_BITS_PER_WORD - 1); // Fill with sign bit.
976 else
977 U.VAL = SExtVAL >> ShiftAmt;
978 clearUnusedBits();
979 return;
980 }
981 ashrSlowCase(ShiftAmt);
982 }
983
984 /// Logical right-shift function.
985 ///
986 /// Logical right-shift this APInt by shiftAmt.
987 APInt lshr(unsigned shiftAmt) const {
988 APInt R(*this);
989 R.lshrInPlace(shiftAmt);
990 return R;
991 }
992
993 /// Logical right-shift this APInt by ShiftAmt in place.
994 void lshrInPlace(unsigned ShiftAmt) {
995 assert(ShiftAmt <= BitWidth && "Invalid shift amount")((ShiftAmt <= BitWidth && "Invalid shift amount") ?
static_cast<void> (0) : __assert_fail ("ShiftAmt <= BitWidth && \"Invalid shift amount\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 995, __PRETTY_FUNCTION__))
;
996 if (isSingleWord()) {
997 if (ShiftAmt == BitWidth)
998 U.VAL = 0;
999 else
1000 U.VAL >>= ShiftAmt;
1001 return;
1002 }
1003 lshrSlowCase(ShiftAmt);
1004 }
1005
1006 /// Left-shift function.
1007 ///
1008 /// Left-shift this APInt by shiftAmt.
1009 APInt shl(unsigned shiftAmt) const {
1010 APInt R(*this);
1011 R <<= shiftAmt;
1012 return R;
1013 }
1014
1015 /// Rotate left by rotateAmt.
1016 APInt rotl(unsigned rotateAmt) const;
1017
1018 /// Rotate right by rotateAmt.
1019 APInt rotr(unsigned rotateAmt) const;
1020
1021 /// Arithmetic right-shift function.
1022 ///
1023 /// Arithmetic right-shift this APInt by shiftAmt.
1024 APInt ashr(const APInt &ShiftAmt) const {
1025 APInt R(*this);
1026 R.ashrInPlace(ShiftAmt);
1027 return R;
1028 }
1029
1030 /// Arithmetic right-shift this APInt by shiftAmt in place.
1031 void ashrInPlace(const APInt &shiftAmt);
1032
1033 /// Logical right-shift function.
1034 ///
1035 /// Logical right-shift this APInt by shiftAmt.
1036 APInt lshr(const APInt &ShiftAmt) const {
1037 APInt R(*this);
1038 R.lshrInPlace(ShiftAmt);
1039 return R;
1040 }
1041
1042 /// Logical right-shift this APInt by ShiftAmt in place.
1043 void lshrInPlace(const APInt &ShiftAmt);
1044
1045 /// Left-shift function.
1046 ///
1047 /// Left-shift this APInt by shiftAmt.
1048 APInt shl(const APInt &ShiftAmt) const {
1049 APInt R(*this);
1050 R <<= ShiftAmt;
1051 return R;
1052 }
1053
1054 /// Rotate left by rotateAmt.
1055 APInt rotl(const APInt &rotateAmt) const;
1056
1057 /// Rotate right by rotateAmt.
1058 APInt rotr(const APInt &rotateAmt) const;
1059
1060 /// Unsigned division operation.
1061 ///
1062 /// Perform an unsigned divide operation on this APInt by RHS. Both this and
1063 /// RHS are treated as unsigned quantities for purposes of this division.
1064 ///
1065 /// \returns a new APInt value containing the division result, rounded towards
1066 /// zero.
1067 APInt udiv(const APInt &RHS) const;
1068 APInt udiv(uint64_t RHS) const;
1069
1070 /// Signed division function for APInt.
1071 ///
1072 /// Signed divide this APInt by APInt RHS.
1073 ///
1074 /// The result is rounded towards zero.
1075 APInt sdiv(const APInt &RHS) const;
1076 APInt sdiv(int64_t RHS) const;
1077
1078 /// Unsigned remainder operation.
1079 ///
1080 /// Perform an unsigned remainder operation on this APInt with RHS being the
1081 /// divisor. Both this and RHS are treated as unsigned quantities for purposes
1082 /// of this operation. Note that this is a true remainder operation and not a
1083 /// modulo operation because the sign follows the sign of the dividend which
1084 /// is *this.
1085 ///
1086 /// \returns a new APInt value containing the remainder result
1087 APInt urem(const APInt &RHS) const;
1088 uint64_t urem(uint64_t RHS) const;
1089
1090 /// Function for signed remainder operation.
1091 ///
1092 /// Signed remainder operation on APInt.
1093 APInt srem(const APInt &RHS) const;
1094 int64_t srem(int64_t RHS) const;
1095
1096 /// Dual division/remainder interface.
1097 ///
1098 /// Sometimes it is convenient to divide two APInt values and obtain both the
1099 /// quotient and remainder. This function does both operations in the same
1100 /// computation making it a little more efficient. The pair of input arguments
1101 /// may overlap with the pair of output arguments. It is safe to call
1102 /// udivrem(X, Y, X, Y), for example.
1103 static void udivrem(const APInt &LHS, const APInt &RHS, APInt &Quotient,
1104 APInt &Remainder);
1105 static void udivrem(const APInt &LHS, uint64_t RHS, APInt &Quotient,
1106 uint64_t &Remainder);
1107
1108 static void sdivrem(const APInt &LHS, const APInt &RHS, APInt &Quotient,
1109 APInt &Remainder);
1110 static void sdivrem(const APInt &LHS, int64_t RHS, APInt &Quotient,
1111 int64_t &Remainder);
1112
1113 // Operations that return overflow indicators.
1114 APInt sadd_ov(const APInt &RHS, bool &Overflow) const;
1115 APInt uadd_ov(const APInt &RHS, bool &Overflow) const;
1116 APInt ssub_ov(const APInt &RHS, bool &Overflow) const;
1117 APInt usub_ov(const APInt &RHS, bool &Overflow) const;
1118 APInt sdiv_ov(const APInt &RHS, bool &Overflow) const;
1119 APInt smul_ov(const APInt &RHS, bool &Overflow) const;
1120 APInt umul_ov(const APInt &RHS, bool &Overflow) const;
1121 APInt sshl_ov(const APInt &Amt, bool &Overflow) const;
1122 APInt ushl_ov(const APInt &Amt, bool &Overflow) const;
1123
1124 // Operations that saturate
1125 APInt sadd_sat(const APInt &RHS) const;
1126 APInt uadd_sat(const APInt &RHS) const;
1127 APInt ssub_sat(const APInt &RHS) const;
1128 APInt usub_sat(const APInt &RHS) const;
1129 APInt smul_sat(const APInt &RHS) const;
1130 APInt umul_sat(const APInt &RHS) const;
1131 APInt sshl_sat(const APInt &RHS) const;
1132 APInt ushl_sat(const APInt &RHS) const;
1133
1134 /// Array-indexing support.
1135 ///
1136 /// \returns the bit value at bitPosition
1137 bool operator[](unsigned bitPosition) const {
1138 assert(bitPosition < getBitWidth() && "Bit position out of bounds!")((bitPosition < getBitWidth() && "Bit position out of bounds!"
) ? static_cast<void> (0) : __assert_fail ("bitPosition < getBitWidth() && \"Bit position out of bounds!\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 1138, __PRETTY_FUNCTION__))
;
1139 return (maskBit(bitPosition) & getWord(bitPosition)) != 0;
1140 }
1141
1142 /// @}
1143 /// \name Comparison Operators
1144 /// @{
1145
1146 /// Equality operator.
1147 ///
1148 /// Compares this APInt with RHS for the validity of the equality
1149 /// relationship.
1150 bool operator==(const APInt &RHS) const {
1151 assert(BitWidth == RHS.BitWidth && "Comparison requires equal bit widths")((BitWidth == RHS.BitWidth && "Comparison requires equal bit widths"
) ? static_cast<void> (0) : __assert_fail ("BitWidth == RHS.BitWidth && \"Comparison requires equal bit widths\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 1151, __PRETTY_FUNCTION__))
;
1152 if (isSingleWord())
1153 return U.VAL == RHS.U.VAL;
1154 return EqualSlowCase(RHS);
1155 }
1156
1157 /// Equality operator.
1158 ///
1159 /// Compares this APInt with a uint64_t for the validity of the equality
1160 /// relationship.
1161 ///
1162 /// \returns true if *this == Val
1163 bool operator==(uint64_t Val) const {
1164 return (isSingleWord() || getActiveBits() <= 64) && getZExtValue() == Val;
1165 }
1166
1167 /// Equality comparison.
1168 ///
1169 /// Compares this APInt with RHS for the validity of the equality
1170 /// relationship.
1171 ///
1172 /// \returns true if *this == Val
1173 bool eq(const APInt &RHS) const { return (*this) == RHS; }
1174
1175 /// Inequality operator.
1176 ///
1177 /// Compares this APInt with RHS for the validity of the inequality
1178 /// relationship.
1179 ///
1180 /// \returns true if *this != Val
1181 bool operator!=(const APInt &RHS) const { return !((*this) == RHS); }
1182
1183 /// Inequality operator.
1184 ///
1185 /// Compares this APInt with a uint64_t for the validity of the inequality
1186 /// relationship.
1187 ///
1188 /// \returns true if *this != Val
1189 bool operator!=(uint64_t Val) const { return !((*this) == Val); }
1190
1191 /// Inequality comparison
1192 ///
1193 /// Compares this APInt with RHS for the validity of the inequality
1194 /// relationship.
1195 ///
1196 /// \returns true if *this != Val
1197 bool ne(const APInt &RHS) const { return !((*this) == RHS); }
1198
1199 /// Unsigned less than comparison
1200 ///
1201 /// Regards both *this and RHS as unsigned quantities and compares them for
1202 /// the validity of the less-than relationship.
1203 ///
1204 /// \returns true if *this < RHS when both are considered unsigned.
1205 bool ult(const APInt &RHS) const { return compare(RHS) < 0; }
1206
1207 /// Unsigned less than comparison
1208 ///
1209 /// Regards both *this as an unsigned quantity and compares it with RHS for
1210 /// the validity of the less-than relationship.
1211 ///
1212 /// \returns true if *this < RHS when considered unsigned.
1213 bool ult(uint64_t RHS) const {
1214 // Only need to check active bits if not a single word.
1215 return (isSingleWord() || getActiveBits() <= 64) && getZExtValue() < RHS;
1216 }
1217
1218 /// Signed less than comparison
1219 ///
1220 /// Regards both *this and RHS as signed quantities and compares them for
1221 /// validity of the less-than relationship.
1222 ///
1223 /// \returns true if *this < RHS when both are considered signed.
1224 bool slt(const APInt &RHS) const { return compareSigned(RHS) < 0; }
1225
1226 /// Signed less than comparison
1227 ///
1228 /// Regards both *this as a signed quantity and compares it with RHS for
1229 /// the validity of the less-than relationship.
1230 ///
1231 /// \returns true if *this < RHS when considered signed.
1232 bool slt(int64_t RHS) const {
1233 return (!isSingleWord() && getMinSignedBits() > 64) ? isNegative()
1234 : getSExtValue() < RHS;
1235 }
1236
1237 /// Unsigned less or equal comparison
1238 ///
1239 /// Regards both *this and RHS as unsigned quantities and compares them for
1240 /// validity of the less-or-equal relationship.
1241 ///
1242 /// \returns true if *this <= RHS when both are considered unsigned.
1243 bool ule(const APInt &RHS) const { return compare(RHS) <= 0; }
1244
1245 /// Unsigned less or equal comparison
1246 ///
1247 /// Regards both *this as an unsigned quantity and compares it with RHS for
1248 /// the validity of the less-or-equal relationship.
1249 ///
1250 /// \returns true if *this <= RHS when considered unsigned.
1251 bool ule(uint64_t RHS) const { return !ugt(RHS); }
1252
1253 /// Signed less or equal comparison
1254 ///
1255 /// Regards both *this and RHS as signed quantities and compares them for
1256 /// validity of the less-or-equal relationship.
1257 ///
1258 /// \returns true if *this <= RHS when both are considered signed.
1259 bool sle(const APInt &RHS) const { return compareSigned(RHS) <= 0; }
1260
1261 /// Signed less or equal comparison
1262 ///
1263 /// Regards both *this as a signed quantity and compares it with RHS for the
1264 /// validity of the less-or-equal relationship.
1265 ///
1266 /// \returns true if *this <= RHS when considered signed.
1267 bool sle(uint64_t RHS) const { return !sgt(RHS); }
1268
1269 /// Unsigned greater than comparison
1270 ///
1271 /// Regards both *this and RHS as unsigned quantities and compares them for
1272 /// the validity of the greater-than relationship.
1273 ///
1274 /// \returns true if *this > RHS when both are considered unsigned.
1275 bool ugt(const APInt &RHS) const { return !ule(RHS); }
1276
1277 /// Unsigned greater than comparison
1278 ///
1279 /// Regards both *this as an unsigned quantity and compares it with RHS for
1280 /// the validity of the greater-than relationship.
1281 ///
1282 /// \returns true if *this > RHS when considered unsigned.
1283 bool ugt(uint64_t RHS) const {
1284 // Only need to check active bits if not a single word.
1285 return (!isSingleWord() && getActiveBits() > 64) || getZExtValue() > RHS;
1286 }
1287
1288 /// Signed greater than comparison
1289 ///
1290 /// Regards both *this and RHS as signed quantities and compares them for the
1291 /// validity of the greater-than relationship.
1292 ///
1293 /// \returns true if *this > RHS when both are considered signed.
1294 bool sgt(const APInt &RHS) const { return !sle(RHS); }
1295
1296 /// Signed greater than comparison
1297 ///
1298 /// Regards both *this as a signed quantity and compares it with RHS for
1299 /// the validity of the greater-than relationship.
1300 ///
1301 /// \returns true if *this > RHS when considered signed.
1302 bool sgt(int64_t RHS) const {
1303 return (!isSingleWord() && getMinSignedBits() > 64) ? !isNegative()
1304 : getSExtValue() > RHS;
1305 }
1306
1307 /// Unsigned greater or equal comparison
1308 ///
1309 /// Regards both *this and RHS as unsigned quantities and compares them for
1310 /// validity of the greater-or-equal relationship.
1311 ///
1312 /// \returns true if *this >= RHS when both are considered unsigned.
1313 bool uge(const APInt &RHS) const { return !ult(RHS); }
1314
1315 /// Unsigned greater or equal comparison
1316 ///
1317 /// Regards both *this as an unsigned quantity and compares it with RHS for
1318 /// the validity of the greater-or-equal relationship.
1319 ///
1320 /// \returns true if *this >= RHS when considered unsigned.
1321 bool uge(uint64_t RHS) const { return !ult(RHS); }
1322
1323 /// Signed greater or equal comparison
1324 ///
1325 /// Regards both *this and RHS as signed quantities and compares them for
1326 /// validity of the greater-or-equal relationship.
1327 ///
1328 /// \returns true if *this >= RHS when both are considered signed.
1329 bool sge(const APInt &RHS) const { return !slt(RHS); }
1330
1331 /// Signed greater or equal comparison
1332 ///
1333 /// Regards both *this as a signed quantity and compares it with RHS for
1334 /// the validity of the greater-or-equal relationship.
1335 ///
1336 /// \returns true if *this >= RHS when considered signed.
1337 bool sge(int64_t RHS) const { return !slt(RHS); }
1338
1339 /// This operation tests if there are any pairs of corresponding bits
1340 /// between this APInt and RHS that are both set.
1341 bool intersects(const APInt &RHS) const {
1342 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same")((BitWidth == RHS.BitWidth && "Bit widths must be the same"
) ? static_cast<void> (0) : __assert_fail ("BitWidth == RHS.BitWidth && \"Bit widths must be the same\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 1342, __PRETTY_FUNCTION__))
;
1343 if (isSingleWord())
1344 return (U.VAL & RHS.U.VAL) != 0;
1345 return intersectsSlowCase(RHS);
1346 }
1347
1348 /// This operation checks that all bits set in this APInt are also set in RHS.
1349 bool isSubsetOf(const APInt &RHS) const {
1350 assert(BitWidth == RHS.BitWidth && "Bit widths must be the same")((BitWidth == RHS.BitWidth && "Bit widths must be the same"
) ? static_cast<void> (0) : __assert_fail ("BitWidth == RHS.BitWidth && \"Bit widths must be the same\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 1350, __PRETTY_FUNCTION__))
;
1351 if (isSingleWord())
1352 return (U.VAL & ~RHS.U.VAL) == 0;
1353 return isSubsetOfSlowCase(RHS);
1354 }
1355
1356 /// @}
1357 /// \name Resizing Operators
1358 /// @{
1359
1360 /// Truncate to new width.
1361 ///
1362 /// Truncate the APInt to a specified width. It is an error to specify a width
1363 /// that is greater than or equal to the current width.
1364 APInt trunc(unsigned width) const;
1365
1366 /// Truncate to new width with unsigned saturation.
1367 ///
1368 /// If the APInt, treated as unsigned integer, can be losslessly truncated to
1369 /// the new bitwidth, then return truncated APInt. Else, return max value.
1370 APInt truncUSat(unsigned width) const;
1371
1372 /// Truncate to new width with signed saturation.
1373 ///
1374 /// If this APInt, treated as signed integer, can be losslessly truncated to
1375 /// the new bitwidth, then return truncated APInt. Else, return either
1376 /// signed min value if the APInt was negative, or signed max value.
1377 APInt truncSSat(unsigned width) const;
1378
1379 /// Sign extend to a new width.
1380 ///
1381 /// This operation sign extends the APInt to a new width. If the high order
1382 /// bit is set, the fill on the left will be done with 1 bits, otherwise zero.
1383 /// It is an error to specify a width that is less than or equal to the
1384 /// current width.
1385 APInt sext(unsigned width) const;
1386
1387 /// Zero extend to a new width.
1388 ///
1389 /// This operation zero extends the APInt to a new width. The high order bits
1390 /// are filled with 0 bits. It is an error to specify a width that is less
1391 /// than or equal to the current width.
1392 APInt zext(unsigned width) const;
1393
1394 /// Sign extend or truncate to width
1395 ///
1396 /// Make this APInt have the bit width given by \p width. The value is sign
1397 /// extended, truncated, or left alone to make it that width.
1398 APInt sextOrTrunc(unsigned width) const;
1399
1400 /// Zero extend or truncate to width
1401 ///
1402 /// Make this APInt have the bit width given by \p width. The value is zero
1403 /// extended, truncated, or left alone to make it that width.
1404 APInt zextOrTrunc(unsigned width) const;
1405
1406 /// Sign extend or truncate to width
1407 ///
1408 /// Make this APInt have the bit width given by \p width. The value is sign
1409 /// extended, or left alone to make it that width.
1410 APInt sextOrSelf(unsigned width) const;
1411
1412 /// Zero extend or truncate to width
1413 ///
1414 /// Make this APInt have the bit width given by \p width. The value is zero
1415 /// extended, or left alone to make it that width.
1416 APInt zextOrSelf(unsigned width) const;
1417
1418 /// @}
1419 /// \name Bit Manipulation Operators
1420 /// @{
1421
1422 /// Set every bit to 1.
1423 void setAllBits() {
1424 if (isSingleWord())
1425 U.VAL = WORDTYPE_MAX;
1426 else
1427 // Set all the bits in all the words.
1428 memset(U.pVal, -1, getNumWords() * APINT_WORD_SIZE);
1429 // Clear the unused ones
1430 clearUnusedBits();
1431 }
1432
1433 /// Set a given bit to 1.
1434 ///
1435 /// Set the given bit to 1 whose position is given as "bitPosition".
1436 void setBit(unsigned BitPosition) {
1437 assert(BitPosition < BitWidth && "BitPosition out of range")((BitPosition < BitWidth && "BitPosition out of range"
) ? static_cast<void> (0) : __assert_fail ("BitPosition < BitWidth && \"BitPosition out of range\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 1437, __PRETTY_FUNCTION__))
;
1438 WordType Mask = maskBit(BitPosition);
1439 if (isSingleWord())
1440 U.VAL |= Mask;
1441 else
1442 U.pVal[whichWord(BitPosition)] |= Mask;
1443 }
1444
1445 /// Set the sign bit to 1.
1446 void setSignBit() {
1447 setBit(BitWidth - 1);
1448 }
1449
1450 /// Set a given bit to a given value.
1451 void setBitVal(unsigned BitPosition, bool BitValue) {
1452 if (BitValue)
1453 setBit(BitPosition);
1454 else
1455 clearBit(BitPosition);
1456 }
1457
1458 /// Set the bits from loBit (inclusive) to hiBit (exclusive) to 1.
1459 /// This function handles "wrap" case when \p loBit >= \p hiBit, and calls
1460 /// setBits when \p loBit < \p hiBit.
1461 /// For \p loBit == \p hiBit wrap case, set every bit to 1.
1462 void setBitsWithWrap(unsigned loBit, unsigned hiBit) {
1463 assert(hiBit <= BitWidth && "hiBit out of range")((hiBit <= BitWidth && "hiBit out of range") ? static_cast
<void> (0) : __assert_fail ("hiBit <= BitWidth && \"hiBit out of range\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 1463, __PRETTY_FUNCTION__))
;
1464 assert(loBit <= BitWidth && "loBit out of range")((loBit <= BitWidth && "loBit out of range") ? static_cast
<void> (0) : __assert_fail ("loBit <= BitWidth && \"loBit out of range\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 1464, __PRETTY_FUNCTION__))
;
1465 if (loBit < hiBit) {
1466 setBits(loBit, hiBit);
1467 return;
1468 }
1469 setLowBits(hiBit);
1470 setHighBits(BitWidth - loBit);
1471 }
1472
1473 /// Set the bits from loBit (inclusive) to hiBit (exclusive) to 1.
1474 /// This function handles case when \p loBit <= \p hiBit.
1475 void setBits(unsigned loBit, unsigned hiBit) {
1476 assert(hiBit <= BitWidth && "hiBit out of range")((hiBit <= BitWidth && "hiBit out of range") ? static_cast
<void> (0) : __assert_fail ("hiBit <= BitWidth && \"hiBit out of range\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 1476, __PRETTY_FUNCTION__))
;
1477 assert(loBit <= BitWidth && "loBit out of range")((loBit <= BitWidth && "loBit out of range") ? static_cast
<void> (0) : __assert_fail ("loBit <= BitWidth && \"loBit out of range\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 1477, __PRETTY_FUNCTION__))
;
1478 assert(loBit <= hiBit && "loBit greater than hiBit")((loBit <= hiBit && "loBit greater than hiBit") ? static_cast
<void> (0) : __assert_fail ("loBit <= hiBit && \"loBit greater than hiBit\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 1478, __PRETTY_FUNCTION__))
;
1479 if (loBit == hiBit)
1480 return;
1481 if (loBit < APINT_BITS_PER_WORD && hiBit <= APINT_BITS_PER_WORD) {
1482 uint64_t mask = WORDTYPE_MAX >> (APINT_BITS_PER_WORD - (hiBit - loBit));
1483 mask <<= loBit;
1484 if (isSingleWord())
1485 U.VAL |= mask;
1486 else
1487 U.pVal[0] |= mask;
1488 } else {
1489 setBitsSlowCase(loBit, hiBit);
1490 }
1491 }
1492
1493 /// Set the top bits starting from loBit.
1494 void setBitsFrom(unsigned loBit) {
1495 return setBits(loBit, BitWidth);
1496 }
1497
1498 /// Set the bottom loBits bits.
1499 void setLowBits(unsigned loBits) {
1500 return setBits(0, loBits);
1501 }
1502
1503 /// Set the top hiBits bits.
1504 void setHighBits(unsigned hiBits) {
1505 return setBits(BitWidth - hiBits, BitWidth);
1506 }
1507
1508 /// Set every bit to 0.
1509 void clearAllBits() {
1510 if (isSingleWord())
1511 U.VAL = 0;
1512 else
1513 memset(U.pVal, 0, getNumWords() * APINT_WORD_SIZE);
1514 }
1515
1516 /// Set a given bit to 0.
1517 ///
1518 /// Set the given bit to 0 whose position is given as "bitPosition".
1519 void clearBit(unsigned BitPosition) {
1520 assert(BitPosition < BitWidth && "BitPosition out of range")((BitPosition < BitWidth && "BitPosition out of range"
) ? static_cast<void> (0) : __assert_fail ("BitPosition < BitWidth && \"BitPosition out of range\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 1520, __PRETTY_FUNCTION__))
;
1521 WordType Mask = ~maskBit(BitPosition);
1522 if (isSingleWord())
1523 U.VAL &= Mask;
1524 else
1525 U.pVal[whichWord(BitPosition)] &= Mask;
1526 }
1527
1528 /// Set bottom loBits bits to 0.
1529 void clearLowBits(unsigned loBits) {
1530 assert(loBits <= BitWidth && "More bits than bitwidth")((loBits <= BitWidth && "More bits than bitwidth")
? static_cast<void> (0) : __assert_fail ("loBits <= BitWidth && \"More bits than bitwidth\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 1530, __PRETTY_FUNCTION__))
;
1531 APInt Keep = getHighBitsSet(BitWidth, BitWidth - loBits);
1532 *this &= Keep;
1533 }
1534
1535 /// Set the sign bit to 0.
1536 void clearSignBit() {
1537 clearBit(BitWidth - 1);
1538 }
1539
1540 /// Toggle every bit to its opposite value.
1541 void flipAllBits() {
1542 if (isSingleWord()) {
1543 U.VAL ^= WORDTYPE_MAX;
1544 clearUnusedBits();
1545 } else {
1546 flipAllBitsSlowCase();
1547 }
1548 }
1549
1550 /// Toggles a given bit to its opposite value.
1551 ///
1552 /// Toggle a given bit to its opposite value whose position is given
1553 /// as "bitPosition".
1554 void flipBit(unsigned bitPosition);
1555
1556 /// Negate this APInt in place.
1557 void negate() {
1558 flipAllBits();
1559 ++(*this);
1560 }
1561
1562 /// Insert the bits from a smaller APInt starting at bitPosition.
1563 void insertBits(const APInt &SubBits, unsigned bitPosition);
1564 void insertBits(uint64_t SubBits, unsigned bitPosition, unsigned numBits);
1565
1566 /// Return an APInt with the extracted bits [bitPosition,bitPosition+numBits).
1567 APInt extractBits(unsigned numBits, unsigned bitPosition) const;
1568 uint64_t extractBitsAsZExtValue(unsigned numBits, unsigned bitPosition) const;
1569
1570 /// @}
1571 /// \name Value Characterization Functions
1572 /// @{
1573
1574 /// Return the number of bits in the APInt.
1575 unsigned getBitWidth() const { return BitWidth; }
1576
1577 /// Get the number of words.
1578 ///
1579 /// Here one word's bitwidth equals to that of uint64_t.
1580 ///
1581 /// \returns the number of words to hold the integer value of this APInt.
1582 unsigned getNumWords() const { return getNumWords(BitWidth); }
1583
1584 /// Get the number of words.
1585 ///
1586 /// *NOTE* Here one word's bitwidth equals to that of uint64_t.
1587 ///
1588 /// \returns the number of words to hold the integer value with a given bit
1589 /// width.
1590 static unsigned getNumWords(unsigned BitWidth) {
1591 return ((uint64_t)BitWidth + APINT_BITS_PER_WORD - 1) / APINT_BITS_PER_WORD;
1592 }
1593
1594 /// Compute the number of active bits in the value
1595 ///
1596 /// This function returns the number of active bits which is defined as the
1597 /// bit width minus the number of leading zeros. This is used in several
1598 /// computations to see how "wide" the value is.
1599 unsigned getActiveBits() const { return BitWidth - countLeadingZeros(); }
1600
1601 /// Compute the number of active words in the value of this APInt.
1602 ///
1603 /// This is used in conjunction with getActiveData to extract the raw value of
1604 /// the APInt.
1605 unsigned getActiveWords() const {
1606 unsigned numActiveBits = getActiveBits();
1607 return numActiveBits ? whichWord(numActiveBits - 1) + 1 : 1;
1608 }
1609
1610 /// Get the minimum bit size for this signed APInt
1611 ///
1612 /// Computes the minimum bit width for this APInt while considering it to be a
1613 /// signed (and probably negative) value. If the value is not negative, this
1614 /// function returns the same value as getActiveBits()+1. Otherwise, it
1615 /// returns the smallest bit width that will retain the negative value. For
1616 /// example, -1 can be written as 0b1 or 0xFFFFFFFFFF. 0b1 is shorter and so
1617 /// for -1, this function will always return 1.
1618 unsigned getMinSignedBits() const { return BitWidth - getNumSignBits() + 1; }
1619
1620 /// Get zero extended value
1621 ///
1622 /// This method attempts to return the value of this APInt as a zero extended
1623 /// uint64_t. The bitwidth must be <= 64 or the value must fit within a
1624 /// uint64_t. Otherwise an assertion will result.
1625 uint64_t getZExtValue() const {
1626 if (isSingleWord())
1627 return U.VAL;
1628 assert(getActiveBits() <= 64 && "Too many bits for uint64_t")((getActiveBits() <= 64 && "Too many bits for uint64_t"
) ? static_cast<void> (0) : __assert_fail ("getActiveBits() <= 64 && \"Too many bits for uint64_t\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 1628, __PRETTY_FUNCTION__))
;
1629 return U.pVal[0];
1630 }
1631
1632 /// Get sign extended value
1633 ///
1634 /// This method attempts to return the value of this APInt as a sign extended
1635 /// int64_t. The bit width must be <= 64 or the value must fit within an
1636 /// int64_t. Otherwise an assertion will result.
1637 int64_t getSExtValue() const {
1638 if (isSingleWord())
1639 return SignExtend64(U.VAL, BitWidth);
1640 assert(getMinSignedBits() <= 64 && "Too many bits for int64_t")((getMinSignedBits() <= 64 && "Too many bits for int64_t"
) ? static_cast<void> (0) : __assert_fail ("getMinSignedBits() <= 64 && \"Too many bits for int64_t\""
, "/build/llvm-toolchain-snapshot-12~++20200926111128+c6c5629f2fb/llvm/include/llvm/ADT/APInt.h"
, 1640, __PRETTY_FUNCTION__))
;
1641 return int64_t(U.pVal[0]);
1642 }
1643
1644 /// Get bits required for string value.
1645 ///
1646 /// This method determines how many bits are required to hold the APInt
1647 /// equivalent of the string given by \p str.
1648 static unsigned getBitsNeeded(StringRef str, uint8_t radix);
1649
1650 /// The APInt version of the countLeadingZeros functions in
1651 /// MathExtras.h.
1652 ///
1653 /// It counts the number of zeros from the most significant bit to the first
1654 /// one bit.
1655 ///
1656 /// \returns BitWidth if the value is zero, otherwise returns the number of
1657 /// zeros from the most significant bit to the first one bits.
1658 unsigned countLeadingZeros() const {
1659 if (isSingleWord()) {
1660 unsigned unusedBits = APINT_BITS_PER_WORD - BitWidth;
1661 return llvm::countLeadingZeros(U.VAL) - unusedBits;
1662 }
1663 return countLeadingZerosSlowCase();
1664 }
1665
1666 /// Count the number of leading one bits.
1667 ///
1668 /// This function is an APInt version of the countLeadingOnes
1669 /// functions in MathExtras.h. It counts the number of ones from the most
1670 /// significant bit to the first zero bit.
1671 ///
1672 /// \returns 0 if the high order bit is not set, otherwise returns the number
1673 /// of 1 bits from the most significant to the least
1674 unsigned countLeadingOnes() const {
1675 if (isSingleWord())
1676 return llvm::countLeadingOnes(U.VAL << (APINT_BITS_PER_WORD - BitWidth));
1677 return countLeadingOnesSlowCase();
1678 }
1679
1680 /// Computes the number of leading bits of this APInt that are equal to its
1681 /// sign bit.
1682 unsigned getNumSignBits() const {
1683 return isNegative() ? countLeadingOnes() : countLeadingZeros();
1684 }
1685
1686 /// Count the number of trailing zero bits.
1687 ///
1688 /// This function is an APInt version of the countTrailingZeros
1689 /// functions in MathExtras.h. It counts the number of zeros from the least
1690 /// significant bit to the first set bit.
1691 ///
1692 /// \returns BitWidth if the value is zero, otherwise returns the number of
1693 /// zeros from the least significant bit to the first one bit.
1694 unsigned countTrailingZeros() const {
1695 if (isSingleWord())
1696 return std::min(unsigned(llvm::countTrailingZeros(U.VAL)), BitWidth);
1697 return countTrailingZerosSlowCase();
1698 }
1699
1700 /// Count the number of trailing one bits.
1701 ///
1702 /// This function is an APInt version of the countTrailingOnes
1703 /// functions in MathExtras.h. It counts the number of ones from the least
1704 /// significant bit to the first zero bit.
1705 ///
1706 /// \returns BitWidth if the value is all ones, otherwise returns the number
1707 /// of ones from the least significant bit to the first zero bit.
1708 unsigned countTrailingOnes() const {
1709 if (isSingleWord())
1710 return llvm::countTrailingOnes(U.VAL);
1711 return countTrailingOnesSlowCase();
1712 }
1713
1714 /// Count the number of bits set.
1715 ///
1716 /// This function is an APInt version of the countPopulation functions
1717 /// in MathExtras.h. It counts the number of 1 bits in the APInt value.
1718 ///
1719 /// \returns 0 if the value is zero, otherwise returns the number of set bits.
1720 unsigned countPopulation() const {
1721 if (isSingleWord())
1722 return llvm::countPopulation(U.VAL);
1723 return countPopulationSlowCase();
1724 }
1725
1726 /// @}
1727 /// \name Conversion Functions
1728 /// @{
1729 void print(raw_ostream &OS, bool isSigned) const;
1730
1731 /// Converts an APInt to a string and append it to Str. Str is commonly a
1732 /// SmallString.
1733 void toString(SmallVectorImpl<char> &Str, unsigned Radix, bool Signed,
1734 bool formatAsCLiteral = false) const;
1735
1736 /// Considers the APInt to be unsigned and converts it into a string in the
1737 /// radix given. The radix can be 2, 8, 10 16, or 36.
1738 void toStringUnsigned(SmallVectorImpl<char> &Str, unsigned Radix = 10) const {
1739 toString(Str, Radix, false, false);
1740 }
1741
1742 /// Considers the APInt to be signed and converts it into a string in the
1743 /// radix given. The radix can be 2, 8, 10, 16, or 36.
1744 void toStringSigned(SmallVectorImpl<char> &Str, unsigned Radix = 10) const {
1745 toString(Str, Radix, true, false);
1746 }
1747
1748 /// Return the APInt as a std::string.
1749 ///
1750 /// Note that this is an inefficient method. It is better to pass in a
1751 /// SmallVector/SmallString to the methods above to avoid thrashing the heap
1752 /// for the string.
1753 std::string toString(unsigned Radix, bool Signed) const;
1754
1755 /// \returns a byte-swapped representation of this APInt Value.
1756 APInt byteSwap() const;
1757
1758 /// \returns the value with the bit representation reversed of this APInt
1759 /// Value.
1760 APInt reverseBits() const;
1761
1762 /// Converts this APInt to a double value.
1763 double roundToDouble(bool isSigned) const;
1764
1765 /// Converts this unsigned APInt to a double value.
1766 double roundToDouble() const { return roundToDouble(false); }
1767
1768 /// Converts this signed APInt to a double value.
1769 double signedRoundToDouble() const { return roundToDouble(true); }
1770
1771 /// Converts APInt bits to a double
1772 ///
1773 /// The conversion does not do a translation from integer to double, it just
1774 /// re-interprets the bits as a double. Note that it is valid to do this on
1775 /// any bit width. Exactly 64 bits will be translated.
1776 double bitsToDouble() const {
1777 return BitsToDouble(getWord(0));
1778 }
1779
1780 /// Converts APInt bits to a float
1781 ///
1782 /// The conversion does not do a translation from integer to float, it just
1783 /// re-interprets the bits as a float. Note that it is valid to do this on
1784 /// any bit width. Exactly 32 bits will be translated.
1785 float bitsToFloat() const {
1786 return BitsToFloat(static_cast<uint32_t>(getWord(0)));
1787 }
1788
1789 /// Converts a double to APInt bits.
1790 ///
1791 /// The conversion does not do a translation from double to integer, it just
1792 /// re-interprets the bits of the double.
1793 static APInt doubleToBits(double V) {
1794 return APInt(sizeof(double) * CHAR_BIT8, DoubleToBits(V));
1795 }
1796
1797 /// Converts a float to APInt bits.
1798 ///
1799 /// The conversion does not do a translation from float to integer, it just
1800 /// re-interprets the bits of the float.
1801 static APInt floatToBits(float V) {
1802 return APInt(sizeof(float) * CHAR_BIT8, FloatToBits(V));
1803 }
1804
1805 /// @}
1806 /// \name Mathematics Operations
1807 /// @{
1808
1809 /// \returns the floor log base 2 of this APInt.
1810 unsigned logBase2() const { return getActiveBits() - 1; }
1811
1812 /// \returns the ceil log base 2 of this APInt.
1813 unsigned ceilLogBase2() const {
1814 APInt temp(*this);
1815 --temp;
1816 return temp.getActiveBits();
1817 }
1818
1819 /// \returns the nearest log base 2 of this APInt. Ties round up.
1820 ///
1821 /// NOTE: When we have a BitWidth of 1, we define:
1822 ///
1823 /// log2(0) = UINT32_MAX
1824 /// log2(1) = 0
1825 ///
1826 /// to get around any mathematical concerns resulting from
1827 /// referencing 2 in a space where 2 does no exist.
1828 unsigned nearestLogBase2() const {
1829 // Special case when we have a bitwidth of 1. If VAL is 1, then we
1830 // get 0. If VAL is 0, we get WORDTYPE_MAX which gets truncated to
1831 // UINT32_MAX.
1832 if (BitWidth == 1)
1833 return U.VAL - 1;
1834
1835 // Handle the zero case.
1836 if (isNullValue())
1837 return UINT32_MAX(4294967295U);
1838
1839 // The non-zero case is handled by computing:
1840 //
1841 // nearestLogBase2(x) = logBase2(x) + x[logBase2(x)-1].
1842 //
1843 // where x[i] is referring to the value of the ith bit of x.
1844 unsigned lg = logBase2();
1845 return lg + unsigned((*this)[lg - 1]);
1846 }
1847
1848 /// \returns the log base 2 of this APInt if its an exact power of two, -1
1849 /// otherwise
1850 int32_t exactLogBase2() const {
1851 if (!isPowerOf2())
1852 return -1;
1853 return logBase2();
1854 }
1855
1856 /// Compute the square root
1857 APInt sqrt() const;
1858
1859 /// Get the absolute value;
1860 ///
1861 /// If *this is < 0 then return -(*this), otherwise *this;
1862 APInt abs() const {
1863 if (isNegative())
1864 return -(*this);
1865 return *this;
1866 }
1867
1868 /// \returns the multiplicative inverse for a given modulo.
1869 APInt multiplicativeInverse(const APInt &modulo) const;
1870
1871 /// @}
1872 /// \name Support for division by constant
1873 /// @{
1874
1875 /// Calculate the magic number for signed division by a constant.
1876 struct ms;
1877 ms magic() const;
1878
1879 /// Calculate the magic number for unsigned division by a constant.
1880 struct mu;
1881 mu magicu(unsigned LeadingZeros = 0) const;
1882
1883 /// @}
1884 /// \name Building-block Operations for APInt and APFloat
1885 /// @{
1886
1887 // These building block operations operate on a representation of arbitrary
1888 // precision, two's-complement, bignum integer values. They should be
1889 // sufficient to implement APInt and APFloat bignum requirements. Inputs are
1890 // generally a pointer to the base of an array of integer parts, representing
1891 // an unsigned bignum, and a count of how many parts there are.
1892
1893 /// Sets the least significant part of a bignum to the input value, and zeroes
1894 /// out higher parts.
1895 static void tcSet(WordType *, WordType, unsigned);
1896
1897 /// Assign one bignum to another.
1898 static void tcAssign(WordType *, const WordType *, unsigned);
1899
1900 /// Returns true if a bignum is zero, false otherwise.
1901 static bool tcIsZero(const WordType *, unsigned);
1902
1903 /// Extract the given bit of a bignum; returns 0 or 1. Zero-based.
1904 static int tcExtractBit(const WordType *, unsigned bit);
1905
1906 /// Copy the bit vector of width srcBITS from SRC, starting at bit srcLSB, to
1907 /// DST, of dstCOUNT parts, such that the bit srcLSB becomes the least
1908 /// significant bit of DST. All high bits above srcBITS in DST are
1909 /// zero-filled.
1910 static void tcExtract(WordType *, unsigned dstCount,
1911 const WordType *, unsigned srcBits,
1912 unsigned srcLSB);
1913
1914 /// Set the given bit of a bignum. Zero-based.
1915 static void tcSetBit(WordType *, unsigned bit);
1916
1917 /// Clear the given bit of a bignum. Zero-based.
1918 static void tcClearBit(WordType *, unsigned bit);
1919
1920 /// Returns the bit number of the least or most significant set bit of a
1921 /// number. If the input number has no bits set -1U is returned.
1922 static unsigned tcLSB(const WordType *, unsigned n);
1923 static unsigned tcMSB(const WordType *parts, unsigned n);
1924
1925 /// Negate a bignum in-place.
1926 static void tcNegate(WordType *, unsigned);
1927
1928 /// DST += RHS + CARRY where CARRY is zero or one. Returns the carry flag.
1929 static WordType tcAdd(WordType *, const WordType *,
1930 WordType carry, unsigned);
1931 /// DST += RHS. Returns the carry flag.
1932 static WordType tcAddPart(WordType *, WordType, unsigned);
1933
1934 /// DST -= RHS + CARRY where CARRY is zero or one. Returns the carry flag.
1935 static WordType tcSubtract(WordType *, const WordType *,
1936 WordType carry, unsigned);
1937 /// DST -= RHS. Returns the carry flag.
1938 static WordType tcSubtractPart(WordType *, WordType, unsigned);
1939
1940 /// DST += SRC * MULTIPLIER + PART if add is true
1941 /// DST = SRC * MULTIPLIER + PART if add is false
1942 ///
1943 /// Requires 0 <= DSTPARTS <= SRCPARTS + 1. If DST overlaps SRC they must
1944 /// start at the same point, i.e. DST == SRC.
1945 ///
1946 /// If DSTPARTS == SRC_PARTS + 1 no overflow occurs and zero is returned.
1947 /// Otherwise DST is filled with the least significant DSTPARTS parts of the
1948 /// result, and if all of the omitted higher parts were zero return zero,
1949 /// otherwise overflow occurred and return one.
1950 static int tcMultiplyPart(WordType *dst, const WordType *src,
1951 WordType multiplier, WordType carry,
1952 unsigned srcParts, unsigned dstParts,
1953 bool add);
1954
1955 /// DST = LHS * RHS, where DST has the same width as the operands and is
1956 /// filled with the least significant parts of the result. Returns one if
1957 /// overflow occurred, otherwise zero. DST must be disjoint from both
1958 /// operands.
1959 static int tcMultiply(WordType *, const WordType *, const WordType *,
1960 unsigned);
1961
1962 /// DST = LHS * RHS, where DST has width the sum of the widths of the
1963 /// operands. No overflow occurs. DST must be disjoint from both operands.
1964 static void tcFullMultiply(WordType *, const WordType *,
1965 const WordType *, unsigned, unsigned);
1966
1967 /// If RHS is zero LHS and REMAINDER are left unchanged, return one.
1968 /// Otherwise set LHS to LHS / RHS with the fractional part discarded, set
1969 /// REMAINDER to the remainder, return zero. i.e.
1970 ///
1971 /// OLD_LHS = RHS * LHS + REMAINDER
1972 ///
1973 /// SCRATCH is a bignum of the same size as the operands and result for use by
1974 /// the routine; its contents need not be initialized and are destroyed. LHS,
1975 /// REMAINDER and SCRATCH must be distinct.
1976 static int tcDivide(WordType *lhs, const WordType *rhs,
1977 WordType *remainder, WordType *scratch,
1978 unsigned parts);
1979
1980 /// Shift a bignum left Count bits. Shifted in bits are zero. There are no
1981 /// restrictions on Count.
1982 static void tcShiftLeft(WordType *, unsigned Words, unsigned Count);
1983
1984 /// Shift a bignum right Count bits. Shifted in bits are zero. There are no
1985 /// restrictions on Count.
1986 static void tcShiftRight(WordType *, unsigned Words, unsigned Count);
1987
1988 /// The obvious AND, OR and XOR and complement operations.
1989 static void tcAnd(WordType *, const WordType *, unsigned);
1990 static void tcOr(WordType *, const WordType *, unsigned);
1991 static void tcXor(WordType *, const WordType *, unsigned);
1992 static void tcComplement(WordType *, unsigned);
1993
1994 /// Comparison (unsigned) of two bignums.
1995 static int tcCompare(const WordType *, const WordType *, unsigned);
1996
1997 /// Increment a bignum in-place. Return the carry flag.
1998 static WordType tcIncrement(WordType *dst, unsigned parts) {
1999 return tcAddPart(dst, 1, parts);
2000 }
2001
2002 /// Decrement a bignum in-place. Return the borrow flag.
2003 static WordType tcDecrement(WordType *dst, unsigned parts) {
2004 return tcSubtractPart(dst, 1, parts);
2005 }
2006
2007 /// Set the least significant BITS and clear the rest.
2008 static void tcSetLeastSignificantBits(WordType *, unsigned, unsigned bits);
2009
2010 /// debug method
2011 void dump() const;
2012
2013 /// @}
2014};
2015
2016/// Magic data for optimising signed division by a constant.
2017struct APInt::ms {
2018 APInt m; ///< magic number
2019 unsigned s; ///< shift amount
2020};
2021
2022/// Magic data for optimising unsigned division by a constant.
2023struct APInt::mu {
2024 APInt m; ///< magic number
2025 bool a; ///< add indicator
2026 unsigned s; ///< shift amount
2027};
2028
2029inline bool operator==(uint64_t V1, const APInt &V2) { return V2 == V1; }
2030
2031inline bool operator!=(uint64_t V1, const APInt &V2) { return V2 != V1; }
2032
2033/// Unary bitwise complement operator.
2034///
2035/// \returns an APInt that is the bitwise complement of \p v.
2036inline APInt operator~(APInt v) {
2037 v.flipAllBits();
2038 return v;
2039}
2040
2041inline APInt operator&(APInt a, const APInt &b) {
2042 a &= b;
2043 return a;
2044}
2045
2046inline APInt operator&(const APInt &a, APInt &&b) {
2047 b &= a;
2048 return std::move(b);
2049}
2050
2051inline APInt operator&(APInt a, uint64_t RHS) {
2052 a &= RHS;
2053 return a;
2054}
2055
2056inline APInt operator&(uint64_t LHS, APInt b) {
2057 b &= LHS;
2058 return b;
2059}
2060
2061inline APInt operator|(APInt a, const APInt &b) {
2062 a |= b;
2063 return a;
2064}
2065
2066inline APInt operator|(const APInt &a, APInt &&b) {
2067 b |= a;
2068 return std::move(b);
2069}
2070
2071inline APInt operator|(APInt a, uint64_t RHS) {
2072 a |= RHS;
2073 return a;
2074}
2075
2076inline APInt operator|(uint64_t LHS, APInt b) {
2077 b |= LHS;
2078 return b;
2079}
2080
2081inline APInt operator^(APInt a, const APInt &b) {
2082 a ^= b;
2083 return a;
2084}
2085
2086inline APInt operator^(const APInt &a, APInt &&b) {
2087 b ^= a;
2088 return std::move(b);
2089}
2090
2091inline APInt operator^(APInt a, uint64_t RHS) {
2092 a ^= RHS;
2093 return a;
2094}
2095
2096inline APInt operator^(uint64_t LHS, APInt b) {
2097 b ^= LHS;
2098 return b;
2099}
2100
2101inline raw_ostream &operator<<(raw_ostream &OS, const APInt &I) {
2102 I.print(OS, true);
2103 return OS;
2104}
2105
2106inline APInt operator-(APInt v) {
2107 v.negate();
2108 return v;
2109}
2110
2111inline APInt operator+(APInt a, const APInt &b) {
2112 a += b;
2113 return a;
2114}
2115
2116inline APInt operator+(const APInt &a, APInt &&b) {
2117 b += a;
2118 return std::move(b);
2119}
2120
2121inline APInt operator+(APInt a, uint64_t RHS) {
2122 a += RHS;
2123 return a;
2124}
2125
2126inline APInt operator+(uint64_t LHS, APInt b) {
2127 b += LHS;
2128 return b;
2129}
2130
2131inline APInt operator-(APInt a, const APInt &b) {
2132 a -= b;
2133 return a;
2134}
2135
2136inline APInt operator-(const APInt &a, APInt &&b) {
2137 b.negate();
2138 b += a;
2139 return std::move(b);
2140}
2141
2142inline APInt operator-(APInt a, uint64_t RHS) {
2143 a -= RHS;
2144 return a;
2145}
2146
2147inline APInt operator-(uint64_t LHS, APInt b) {
2148 b.negate();
2149 b += LHS;
2150 return b;
2151}
2152
2153inline APInt operator*(APInt a, uint64_t RHS) {
2154 a *= RHS;
2155 return a;
2156}
2157
2158inline APInt operator*(uint64_t LHS, APInt b) {
2159 b *= LHS;
2160 return b;
2161}
2162
2163
2164namespace APIntOps {
2165
2166/// Determine the smaller of two APInts considered to be signed.
2167inline const APInt &smin(const APInt &A, const APInt &B) {
2168 return A.slt(B) ? A : B;
2169}
2170
2171/// Determine the larger of two APInts considered to be signed.
2172inline const APInt &smax(const APInt &A, const APInt &B) {
2173 return A.sgt(B) ? A : B;
2174}
2175
2176/// Determine the smaller of two APInts considered to be signed.
2177inline const APInt &umin(const APInt &A, const APInt &B) {
2178 return A.ult(B) ? A : B;
2179}
2180
2181/// Determine the larger of two APInts considered to be unsigned.
2182inline const APInt &umax(const APInt &A, const APInt &B) {
2183 return A.ugt(B) ? A : B;
2184}
2185
2186/// Compute GCD of two unsigned APInt values.
2187///
2188/// This function returns the greatest common divisor of the two APInt values
2189/// using Stein's algorithm.
2190///
2191/// \returns the greatest common divisor of A and B.
2192APInt GreatestCommonDivisor(APInt A, APInt B);
2193
2194/// Converts the given APInt to a double value.
2195///
2196/// Treats the APInt as an unsigned value for conversion purposes.
2197inline double RoundAPIntToDouble(const APInt &APIVal) {
2198 return APIVal.roundToDouble();
2199}
2200
2201/// Converts the given APInt to a double value.
2202///
2203/// Treats the APInt as a signed value for conversion purposes.
2204inline double RoundSignedAPIntToDouble(const APInt &APIVal) {
2205 return APIVal.signedRoundToDouble();
2206}
2207
2208/// Converts the given APInt to a float vlalue.
2209inline float RoundAPIntToFloat(const APInt &APIVal) {
2210 return float(RoundAPIntToDouble(APIVal));
2211}
2212
2213/// Converts the given APInt to a float value.
2214///
2215/// Treats the APInt as a signed value for conversion purposes.
2216inline float RoundSignedAPIntToFloat(const APInt &APIVal) {
2217 return float(APIVal.signedRoundToDouble());
2218}
2219
2220/// Converts the given double value into a APInt.
2221///
2222/// This function convert a double value to an APInt value.
2223APInt RoundDoubleToAPInt(double Double, unsigned width);
2224
2225/// Converts a float value into a APInt.
2226///
2227/// Converts a float value into an APInt value.
2228inline APInt RoundFloatToAPInt(float Float, unsigned width) {
2229 return RoundDoubleToAPInt(double(Float), width);
2230}
2231
2232/// Return A unsign-divided by B, rounded by the given rounding mode.
2233APInt RoundingUDiv(const APInt &A, const APInt &B, APInt::Rounding RM);
2234
2235/// Return A sign-divided by B, rounded by the given rounding mode.
2236APInt RoundingSDiv(const APInt &A, const APInt &B, APInt::Rounding RM);
2237
2238/// Let q(n) = An^2 + Bn + C, and BW = bit width of the value range
2239/// (e.g. 32 for i32).
2240/// This function finds the smallest number n, such that
2241/// (a) n >= 0 and q(n) = 0, or
2242/// (b) n >= 1 and q(n-1) and q(n), when evaluated in the set of all
2243/// integers, belong to two different intervals [Rk, Rk+R),
2244/// where R = 2^BW, and k is an integer.
2245/// The idea here is to find when q(n) "overflows" 2^BW, while at the
2246/// same time "allowing" subtraction. In unsigned modulo arithmetic a
2247/// subtraction (treated as addition of negated numbers) would always
2248/// count as an overflow, but here we want to allow values to decrease
2249/// and increase as long as they are within the same interval.
2250/// Specifically, adding of two negative numbers should not cause an
2251/// overflow (as long as the magnitude does not exceed the bit width).
2252/// On the other hand, given a positive number, adding a negative
2253/// number to it can give a negative result, which would cause the
2254/// value to go from [-2^BW, 0) to [0, 2^BW). In that sense, zero is
2255/// treated as a special case of an overflow.
2256///
2257/// This function returns None if after finding k that minimizes the
2258/// positive solution to q(n) = kR, both solutions are contained between
2259/// two consecutive integers.
2260///
2261/// There are cases where q(n) > T, and q(n+1) < T (assuming evaluation
2262/// in arithmetic modulo 2^BW, and treating the values as signed) by the
2263/// virtue of *signed* overflow. This function will *not* find such an n,
2264/// however it may find a value of n satisfying the inequalities due to
2265/// an *unsigned* overflow (if the values are treated as unsigned).
2266/// To find a solution for a signed overflow, treat it as a problem of
2267/// finding an unsigned overflow with a range with of BW-1.
2268///
2269/// The returned value may have a different bit width from the input
2270/// coefficients.
2271Optional<APInt> SolveQuadraticEquationWrap(APInt A, APInt B, APInt C,
2272 unsigned RangeWidth);
2273
2274/// Compare two values, and if they are different, return the position of the
2275/// most significant bit that is different in the values.
2276Optional<unsigned> GetMostSignificantDifferentBit(const APInt &A,
2277 const APInt &B);
2278
2279} // End of APIntOps namespace
2280
2281// See friend declaration above. This additional declaration is required in
2282// order to compile LLVM with IBM xlC compiler.
2283hash_code hash_value(const APInt &Arg);
2284
2285/// StoreIntToMemory - Fills the StoreBytes bytes of memory starting from Dst
2286/// with the integer held in IntVal.
2287void StoreIntToMemory(const APInt &IntVal, uint8_t *Dst, unsigned StoreBytes);
2288
2289/// LoadIntFromMemory - Loads the integer stored in the LoadBytes bytes starting
2290/// from Src into IntVal, which is assumed to be wide enough and to hold zero.
2291void LoadIntFromMemory(APInt &IntVal, const uint8_t *Src, unsigned LoadBytes);
2292
2293} // namespace llvm
2294
2295#endif