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~++20201129111111+e987fbdd85d/build-llvm/lib/Analysis -I /build/llvm-toolchain-snapshot-12~++20201129111111+e987fbdd85d/llvm/lib/Analysis -I /build/llvm-toolchain-snapshot-12~++20201129111111+e987fbdd85d/build-llvm/include -I /build/llvm-toolchain-snapshot-12~++20201129111111+e987fbdd85d/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~++20201129111111+e987fbdd85d/build-llvm/lib/Analysis -fdebug-prefix-map=/build/llvm-toolchain-snapshot-12~++20201129111111+e987fbdd85d=. -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-2020-11-29-190409-37574-1 -x c++ /build/llvm-toolchain-snapshot-12~++20201129111111+e987fbdd85d/llvm/lib/Analysis/BasicAliasAnalysis.cpp

/build/llvm-toolchain-snapshot-12~++20201129111111+e987fbdd85d/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/ScopeExit.h"
18#include "llvm/ADT/SmallPtrSet.h"
19#include "llvm/ADT/SmallVector.h"
20#include "llvm/ADT/Statistic.h"
21#include "llvm/Analysis/AliasAnalysis.h"
22#include "llvm/Analysis/AssumptionCache.h"
23#include "llvm/Analysis/CFG.h"
24#include "llvm/Analysis/CaptureTracking.h"
25#include "llvm/Analysis/InstructionSimplify.h"
26#include "llvm/Analysis/LoopInfo.h"
27#include "llvm/Analysis/MemoryBuiltins.h"
28#include "llvm/Analysis/MemoryLocation.h"
29#include "llvm/Analysis/PhiValues.h"
30#include "llvm/Analysis/TargetLibraryInfo.h"
31#include "llvm/Analysis/ValueTracking.h"
32#include "llvm/IR/Argument.h"
33#include "llvm/IR/Attributes.h"
34#include "llvm/IR/Constant.h"
35#include "llvm/IR/Constants.h"
36#include "llvm/IR/DataLayout.h"
37#include "llvm/IR/DerivedTypes.h"
38#include "llvm/IR/Dominators.h"
39#include "llvm/IR/Function.h"
40#include "llvm/IR/GetElementPtrTypeIterator.h"
41#include "llvm/IR/GlobalAlias.h"
42#include "llvm/IR/GlobalVariable.h"
43#include "llvm/IR/InstrTypes.h"
44#include "llvm/IR/Instruction.h"
45#include "llvm/IR/Instructions.h"
46#include "llvm/IR/IntrinsicInst.h"
47#include "llvm/IR/Intrinsics.h"
48#include "llvm/IR/Metadata.h"
49#include "llvm/IR/Operator.h"
50#include "llvm/IR/Type.h"
51#include "llvm/IR/User.h"
52#include "llvm/IR/Value.h"
53#include "llvm/InitializePasses.h"
54#include "llvm/Pass.h"
55#include "llvm/Support/Casting.h"
56#include "llvm/Support/CommandLine.h"
57#include "llvm/Support/Compiler.h"
58#include "llvm/Support/KnownBits.h"
59#include <cassert>
60#include <cstdint>
61#include <cstdlib>
62#include <utility>
63
64#define DEBUG_TYPE"basicaa" "basicaa"
65
66using namespace llvm;
67
68/// Enable analysis of recursive PHI nodes.
69static cl::opt<bool> EnableRecPhiAnalysis("basic-aa-recphi", cl::Hidden,
70 cl::init(true));
71
72/// By default, even on 32-bit architectures we use 64-bit integers for
73/// calculations. This will allow us to more-aggressively decompose indexing
74/// expressions calculated using i64 values (e.g., long long in C) which is
75/// common enough to worry about.
76static cl::opt<bool> ForceAtLeast64Bits("basic-aa-force-at-least-64b",
77 cl::Hidden, cl::init(true));
78static cl::opt<bool> DoubleCalcBits("basic-aa-double-calc-bits",
79 cl::Hidden, cl::init(false));
80
81/// SearchLimitReached / SearchTimes shows how often the limit of
82/// to decompose GEPs is reached. It will affect the precision
83/// of basic alias analysis.
84STATISTIC(SearchLimitReached, "Number of times the limit to "static llvm::Statistic SearchLimitReached = {"basicaa", "SearchLimitReached"
, "Number of times the limit to " "decompose GEPs is reached"
}
85 "decompose GEPs is reached")static llvm::Statistic SearchLimitReached = {"basicaa", "SearchLimitReached"
, "Number of times the limit to " "decompose GEPs is reached"
}
;
86STATISTIC(SearchTimes, "Number of times a GEP is decomposed")static llvm::Statistic SearchTimes = {"basicaa", "SearchTimes"
, "Number of times a GEP is decomposed"}
;
87
88/// Cutoff after which to stop analysing a set of phi nodes potentially involved
89/// in a cycle. Because we are analysing 'through' phi nodes, we need to be
90/// careful with value equivalence. We use reachability to make sure a value
91/// cannot be involved in a cycle.
92const unsigned MaxNumPhiBBsValueReachabilityCheck = 20;
93
94// The max limit of the search depth in DecomposeGEPExpression() and
95// getUnderlyingObject(), both functions need to use the same search
96// depth otherwise the algorithm in aliasGEP will assert.
97static const unsigned MaxLookupSearchDepth = 6;
98
99bool BasicAAResult::invalidate(Function &Fn, const PreservedAnalyses &PA,
100 FunctionAnalysisManager::Invalidator &Inv) {
101 // We don't care if this analysis itself is preserved, it has no state. But
102 // we need to check that the analyses it depends on have been. Note that we
103 // may be created without handles to some analyses and in that case don't
104 // depend on them.
105 if (Inv.invalidate<AssumptionAnalysis>(Fn, PA) ||
106 (DT && Inv.invalidate<DominatorTreeAnalysis>(Fn, PA)) ||
107 (LI && Inv.invalidate<LoopAnalysis>(Fn, PA)) ||
108 (PV && Inv.invalidate<PhiValuesAnalysis>(Fn, PA)))
109 return true;
110
111 // Otherwise this analysis result remains valid.
112 return false;
113}
114
115//===----------------------------------------------------------------------===//
116// Useful predicates
117//===----------------------------------------------------------------------===//
118
119/// Returns true if the pointer is one which would have been considered an
120/// escape by isNonEscapingLocalObject.
121static bool isEscapeSource(const Value *V) {
122 if (isa<CallBase>(V))
123 return true;
124
125 if (isa<Argument>(V))
126 return true;
127
128 // The load case works because isNonEscapingLocalObject considers all
129 // stores to be escapes (it passes true for the StoreCaptures argument
130 // to PointerMayBeCaptured).
131 if (isa<LoadInst>(V))
132 return true;
133
134 return false;
135}
136
137/// Returns the size of the object specified by V or UnknownSize if unknown.
138static uint64_t getObjectSize(const Value *V, const DataLayout &DL,
139 const TargetLibraryInfo &TLI,
140 bool NullIsValidLoc,
141 bool RoundToAlign = false) {
142 uint64_t Size;
143 ObjectSizeOpts Opts;
144 Opts.RoundToAlign = RoundToAlign;
145 Opts.NullIsUnknownSize = NullIsValidLoc;
146 if (getObjectSize(V, Size, DL, &TLI, Opts))
147 return Size;
148 return MemoryLocation::UnknownSize;
149}
150
151/// Returns true if we can prove that the object specified by V is smaller than
152/// Size.
153static bool isObjectSmallerThan(const Value *V, uint64_t Size,
154 const DataLayout &DL,
155 const TargetLibraryInfo &TLI,
156 bool NullIsValidLoc) {
157 // Note that the meanings of the "object" are slightly different in the
158 // following contexts:
159 // c1: llvm::getObjectSize()
160 // c2: llvm.objectsize() intrinsic
161 // c3: isObjectSmallerThan()
162 // c1 and c2 share the same meaning; however, the meaning of "object" in c3
163 // refers to the "entire object".
164 //
165 // Consider this example:
166 // char *p = (char*)malloc(100)
167 // char *q = p+80;
168 //
169 // In the context of c1 and c2, the "object" pointed by q refers to the
170 // stretch of memory of q[0:19]. So, getObjectSize(q) should return 20.
171 //
172 // However, in the context of c3, the "object" refers to the chunk of memory
173 // being allocated. So, the "object" has 100 bytes, and q points to the middle
174 // the "object". In case q is passed to isObjectSmallerThan() as the 1st
175 // parameter, before the llvm::getObjectSize() is called to get the size of
176 // entire object, we should:
177 // - either rewind the pointer q to the base-address of the object in
178 // question (in this case rewind to p), or
179 // - just give up. It is up to caller to make sure the pointer is pointing
180 // to the base address the object.
181 //
182 // We go for 2nd option for simplicity.
183 if (!isIdentifiedObject(V))
184 return false;
185
186 // This function needs to use the aligned object size because we allow
187 // reads a bit past the end given sufficient alignment.
188 uint64_t ObjectSize = getObjectSize(V, DL, TLI, NullIsValidLoc,
189 /*RoundToAlign*/ true);
190
191 return ObjectSize != MemoryLocation::UnknownSize && ObjectSize < Size;
192}
193
194/// Return the minimal extent from \p V to the end of the underlying object,
195/// assuming the result is used in an aliasing query. E.g., we do use the query
196/// location size and the fact that null pointers cannot alias here.
197static uint64_t getMinimalExtentFrom(const Value &V,
198 const LocationSize &LocSize,
199 const DataLayout &DL,
200 bool NullIsValidLoc) {
201 // If we have dereferenceability information we know a lower bound for the
202 // extent as accesses for a lower offset would be valid. We need to exclude
203 // the "or null" part if null is a valid pointer.
204 bool CanBeNull;
205 uint64_t DerefBytes = V.getPointerDereferenceableBytes(DL, CanBeNull);
206 DerefBytes = (CanBeNull && NullIsValidLoc) ? 0 : DerefBytes;
207 // If queried with a precise location size, we assume that location size to be
208 // accessed, thus valid.
209 if (LocSize.isPrecise())
210 DerefBytes = std::max(DerefBytes, LocSize.getValue());
211 return DerefBytes;
212}
213
214/// Returns true if we can prove that the object specified by V has size Size.
215static bool isObjectSize(const Value *V, uint64_t Size, const DataLayout &DL,
216 const TargetLibraryInfo &TLI, bool NullIsValidLoc) {
217 uint64_t ObjectSize = getObjectSize(V, DL, TLI, NullIsValidLoc);
218 return ObjectSize != MemoryLocation::UnknownSize && ObjectSize == Size;
219}
220
221//===----------------------------------------------------------------------===//
222// GetElementPtr Instruction Decomposition and Analysis
223//===----------------------------------------------------------------------===//
224
225/// Analyzes the specified value as a linear expression: "A*V + B", where A and
226/// B are constant integers.
227///
228/// Returns the scale and offset values as APInts and return V as a Value*, and
229/// return whether we looked through any sign or zero extends. The incoming
230/// Value is known to have IntegerType, and it may already be sign or zero
231/// extended.
232///
233/// Note that this looks through extends, so the high bits may not be
234/// represented in the result.
235/*static*/ const Value *BasicAAResult::GetLinearExpression(
236 const Value *V, APInt &Scale, APInt &Offset, unsigned &ZExtBits,
237 unsigned &SExtBits, const DataLayout &DL, unsigned Depth,
238 AssumptionCache *AC, DominatorTree *DT, bool &NSW, bool &NUW) {
239 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~++20201129111111+e987fbdd85d/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 239, __PRETTY_FUNCTION__))
;
7
'?' condition is true
240
241 // Limit our recursion depth.
242 if (Depth
7.1
'Depth' is not equal to 6
7.1
'Depth' is not equal to 6
== 6) {
8
Taking false branch
243 Scale = 1;
244 Offset = 0;
245 return V;
246 }
247
248 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
249 // If it's a constant, just convert it to an offset and remove the variable.
250 // If we've been called recursively, the Offset bit width will be greater
251 // than the constant's (the Offset's always as wide as the outermost call),
252 // so we'll zext here and process any extension in the isa<SExtInst> &
253 // isa<ZExtInst> cases below.
254 Offset += Const->getValue().zextOrSelf(Offset.getBitWidth());
255 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~++20201129111111+e987fbdd85d/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 255, __PRETTY_FUNCTION__))
;
256 return V;
257 }
258
259 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
260 if (ConstantInt *RHSC = dyn_cast<ConstantInt>(BOp->getOperand(1))) {
13
Assuming 'RHSC' is non-null
14
Taking true branch
261 // If we've been called recursively, then Offset and Scale will be wider
262 // than the BOp operands. We'll always zext it here as we'll process sign
263 // extensions below (see the isa<SExtInst> / isa<ZExtInst> cases).
264 APInt RHS = RHSC->getValue().zextOrSelf(Offset.getBitWidth());
265
266 switch (BOp->getOpcode()) {
15
Control jumps to 'case Shl:' at line 299
267 default:
268 // We don't understand this instruction, so we can't decompose it any
269 // further.
270 Scale = 1;
271 Offset = 0;
272 return V;
273 case Instruction::Or:
274 // X|C == X+C if all the bits in C are unset in X. Otherwise we can't
275 // analyze it.
276 if (!MaskedValueIsZero(BOp->getOperand(0), RHSC->getValue(), DL, 0, AC,
277 BOp, DT)) {
278 Scale = 1;
279 Offset = 0;
280 return V;
281 }
282 LLVM_FALLTHROUGH[[gnu::fallthrough]];
283 case Instruction::Add:
284 V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, ZExtBits,
285 SExtBits, DL, Depth + 1, AC, DT, NSW, NUW);
286 Offset += RHS;
287 break;
288 case Instruction::Sub:
289 V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, ZExtBits,
290 SExtBits, DL, Depth + 1, AC, DT, NSW, NUW);
291 Offset -= RHS;
292 break;
293 case Instruction::Mul:
294 V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, ZExtBits,
295 SExtBits, DL, Depth + 1, AC, DT, NSW, NUW);
296 Offset *= RHS;
297 Scale *= RHS;
298 break;
299 case Instruction::Shl:
300 V = GetLinearExpression(BOp->getOperand(0), Scale, Offset, ZExtBits,
301 SExtBits, DL, Depth + 1, AC, DT, NSW, NUW);
302
303 // We're trying to linearize an expression of the kind:
304 // shl i8 -128, 36
305 // where the shift count exceeds the bitwidth of the type.
306 // We can't decompose this further (the expression would return
307 // a poison value).
308 if (Offset.getBitWidth() < RHS.getLimitedValue() ||
16
Assuming the condition is false
18
Taking false branch
309 Scale.getBitWidth() < RHS.getLimitedValue()) {
17
Assuming the condition is false
310 Scale = 1;
311 Offset = 0;
312 return V;
313 }
314
315 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<<='
316 Scale <<= RHS.getLimitedValue();
317 // the semantics of nsw and nuw for left shifts don't match those of
318 // multiplications, so we won't propagate them.
319 NSW = NUW = false;
320 return V;
321 }
322
323 if (isa<OverflowingBinaryOperator>(BOp)) {
324 NUW &= BOp->hasNoUnsignedWrap();
325 NSW &= BOp->hasNoSignedWrap();
326 }
327 return V;
328 }
329 }
330
331 // Since GEP indices are sign extended anyway, we don't care about the high
332 // bits of a sign or zero extended value - just scales and offsets. The
333 // extensions have to be consistent though.
334 if (isa<SExtInst>(V) || isa<ZExtInst>(V)) {
335 Value *CastOp = cast<CastInst>(V)->getOperand(0);
336 unsigned NewWidth = V->getType()->getPrimitiveSizeInBits();
337 unsigned SmallWidth = CastOp->getType()->getPrimitiveSizeInBits();
338 unsigned OldZExtBits = ZExtBits, OldSExtBits = SExtBits;
339 const Value *Result =
340 GetLinearExpression(CastOp, Scale, Offset, ZExtBits, SExtBits, DL,
341 Depth + 1, AC, DT, NSW, NUW);
342
343 // zext(zext(%x)) == zext(%x), and similarly for sext; we'll handle this
344 // by just incrementing the number of bits we've extended by.
345 unsigned ExtendedBy = NewWidth - SmallWidth;
346
347 if (isa<SExtInst>(V) && ZExtBits == 0) {
348 // sext(sext(%x, a), b) == sext(%x, a + b)
349
350 if (NSW) {
351 // We haven't sign-wrapped, so it's valid to decompose sext(%x + c)
352 // into sext(%x) + sext(c). We'll sext the Offset ourselves:
353 unsigned OldWidth = Offset.getBitWidth();
354 Offset = Offset.trunc(SmallWidth).sext(NewWidth).zextOrSelf(OldWidth);
355 } else {
356 // We may have signed-wrapped, so don't decompose sext(%x + c) into
357 // sext(%x) + sext(c)
358 Scale = 1;
359 Offset = 0;
360 Result = CastOp;
361 ZExtBits = OldZExtBits;
362 SExtBits = OldSExtBits;
363 }
364 SExtBits += ExtendedBy;
365 } else {
366 // sext(zext(%x, a), b) = zext(zext(%x, a), b) = zext(%x, a + b)
367
368 if (!NUW) {
369 // We may have unsigned-wrapped, so don't decompose zext(%x + c) into
370 // zext(%x) + zext(c)
371 Scale = 1;
372 Offset = 0;
373 Result = CastOp;
374 ZExtBits = OldZExtBits;
375 SExtBits = OldSExtBits;
376 }
377 ZExtBits += ExtendedBy;
378 }
379
380 return Result;
381 }
382
383 Scale = 1;
384 Offset = 0;
385 return V;
386}
387
388/// To ensure a pointer offset fits in an integer of size PointerSize
389/// (in bits) when that size is smaller than the maximum pointer size. This is
390/// an issue, for example, in particular for 32b pointers with negative indices
391/// that rely on two's complement wrap-arounds for precise alias information
392/// where the maximum pointer size is 64b.
393static APInt adjustToPointerSize(const APInt &Offset, unsigned PointerSize) {
394 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~++20201129111111+e987fbdd85d/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 394, __PRETTY_FUNCTION__))
;
395 unsigned ShiftBits = Offset.getBitWidth() - PointerSize;
396 return (Offset << ShiftBits).ashr(ShiftBits);
397}
398
399static unsigned getMaxPointerSize(const DataLayout &DL) {
400 unsigned MaxPointerSize = DL.getMaxPointerSizeInBits();
401 if (MaxPointerSize < 64 && ForceAtLeast64Bits) MaxPointerSize = 64;
402 if (DoubleCalcBits) MaxPointerSize *= 2;
403
404 return MaxPointerSize;
405}
406
407/// If V is a symbolic pointer expression, decompose it into a base pointer
408/// with a constant offset and a number of scaled symbolic offsets.
409///
410/// The scaled symbolic offsets (represented by pairs of a Value* and a scale
411/// in the VarIndices vector) are Value*'s that are known to be scaled by the
412/// specified amount, but which may have other unrepresented high bits. As
413/// such, the gep cannot necessarily be reconstructed from its decomposed form.
414///
415/// This function is capable of analyzing everything that getUnderlyingObject
416/// can look through. To be able to do that getUnderlyingObject and
417/// DecomposeGEPExpression must use the same search depth
418/// (MaxLookupSearchDepth).
419BasicAAResult::DecomposedGEP
420BasicAAResult::DecomposeGEPExpression(const Value *V, const DataLayout &DL,
421 AssumptionCache *AC, DominatorTree *DT) {
422 // Limit recursion depth to limit compile time in crazy cases.
423 unsigned MaxLookup = MaxLookupSearchDepth;
424 SearchTimes++;
425
426 unsigned MaxPointerSize = getMaxPointerSize(DL);
427 DecomposedGEP Decomposed;
428 Decomposed.Offset = APInt(MaxPointerSize, 0);
429 Decomposed.HasCompileTimeConstantScale = true;
430 do {
431 // See if this is a bitcast or GEP.
432 const Operator *Op = dyn_cast<Operator>(V);
433 if (!Op) {
434 // The only non-operator case we can handle are GlobalAliases.
435 if (const GlobalAlias *GA = dyn_cast<GlobalAlias>(V)) {
436 if (!GA->isInterposable()) {
437 V = GA->getAliasee();
438 continue;
439 }
440 }
441 Decomposed.Base = V;
442 return Decomposed;
443 }
444
445 if (Op->getOpcode() == Instruction::BitCast ||
446 Op->getOpcode() == Instruction::AddrSpaceCast) {
447 V = Op->getOperand(0);
448 continue;
449 }
450
451 const GEPOperator *GEPOp = dyn_cast<GEPOperator>(Op);
452 if (!GEPOp) {
453 if (const auto *PHI = dyn_cast<PHINode>(V)) {
454 // Look through single-arg phi nodes created by LCSSA.
455 if (PHI->getNumIncomingValues() == 1) {
456 V = PHI->getIncomingValue(0);
457 continue;
458 }
459 } else if (const auto *Call = dyn_cast<CallBase>(V)) {
460 // CaptureTracking can know about special capturing properties of some
461 // intrinsics like launder.invariant.group, that can't be expressed with
462 // the attributes, but have properties like returning aliasing pointer.
463 // Because some analysis may assume that nocaptured pointer is not
464 // returned from some special intrinsic (because function would have to
465 // be marked with returns attribute), it is crucial to use this function
466 // because it should be in sync with CaptureTracking. Not using it may
467 // cause weird miscompilations where 2 aliasing pointers are assumed to
468 // noalias.
469 if (auto *RP = getArgumentAliasingToReturnedPointer(Call, false)) {
470 V = RP;
471 continue;
472 }
473 }
474
475 Decomposed.Base = V;
476 return Decomposed;
477 }
478
479 // Don't attempt to analyze GEPs over unsized objects.
480 if (!GEPOp->getSourceElementType()->isSized()) {
481 Decomposed.Base = V;
482 return Decomposed;
483 }
484
485 // Don't attempt to analyze GEPs if index scale is not a compile-time
486 // constant.
487 if (isa<ScalableVectorType>(GEPOp->getSourceElementType())) {
488 Decomposed.Base = V;
489 Decomposed.HasCompileTimeConstantScale = false;
490 return Decomposed;
491 }
492
493 unsigned AS = GEPOp->getPointerAddressSpace();
494 // Walk the indices of the GEP, accumulating them into BaseOff/VarIndices.
495 gep_type_iterator GTI = gep_type_begin(GEPOp);
496 unsigned PointerSize = DL.getPointerSizeInBits(AS);
497 // Assume all GEP operands are constants until proven otherwise.
498 bool GepHasConstantOffset = true;
499 for (User::const_op_iterator I = GEPOp->op_begin() + 1, E = GEPOp->op_end();
500 I != E; ++I, ++GTI) {
501 const Value *Index = *I;
502 // Compute the (potentially symbolic) offset in bytes for this index.
503 if (StructType *STy = GTI.getStructTypeOrNull()) {
504 // For a struct, add the member offset.
505 unsigned FieldNo = cast<ConstantInt>(Index)->getZExtValue();
506 if (FieldNo == 0)
507 continue;
508
509 Decomposed.Offset += DL.getStructLayout(STy)->getElementOffset(FieldNo);
510 continue;
511 }
512
513 // For an array/pointer, add the element offset, explicitly scaled.
514 if (const ConstantInt *CIdx = dyn_cast<ConstantInt>(Index)) {
515 if (CIdx->isZero())
516 continue;
517 Decomposed.Offset +=
518 DL.getTypeAllocSize(GTI.getIndexedType()).getFixedSize() *
519 CIdx->getValue().sextOrTrunc(MaxPointerSize);
520 continue;
521 }
522
523 GepHasConstantOffset = false;
524
525 APInt Scale(MaxPointerSize,
526 DL.getTypeAllocSize(GTI.getIndexedType()).getFixedSize());
527 unsigned ZExtBits = 0, SExtBits = 0;
528
529 // If the integer type is smaller than the pointer size, it is implicitly
530 // sign extended to pointer size.
531 unsigned Width = Index->getType()->getIntegerBitWidth();
532 if (PointerSize > Width)
533 SExtBits += PointerSize - Width;
534
535 // Use GetLinearExpression to decompose the index into a C1*V+C2 form.
536 APInt IndexScale(Width, 0), IndexOffset(Width, 0);
537 bool NSW = true, NUW = true;
538 const Value *OrigIndex = Index;
539 Index = GetLinearExpression(Index, IndexScale, IndexOffset, ZExtBits,
540 SExtBits, DL, 0, AC, DT, NSW, NUW);
541
542 // The GEP index scale ("Scale") scales C1*V+C2, yielding (C1*V+C2)*Scale.
543 // This gives us an aggregate computation of (C1*Scale)*V + C2*Scale.
544
545 // It can be the case that, even through C1*V+C2 does not overflow for
546 // relevant values of V, (C2*Scale) can overflow. In that case, we cannot
547 // decompose the expression in this way.
548 //
549 // FIXME: C1*Scale and the other operations in the decomposed
550 // (C1*Scale)*V+C2*Scale can also overflow. We should check for this
551 // possibility.
552 bool Overflow;
553 APInt ScaledOffset = IndexOffset.sextOrTrunc(MaxPointerSize)
554 .smul_ov(Scale, Overflow);
555 if (Overflow) {
556 Index = OrigIndex;
557 IndexScale = 1;
558 IndexOffset = 0;
559
560 ZExtBits = SExtBits = 0;
561 if (PointerSize > Width)
562 SExtBits += PointerSize - Width;
563 } else {
564 Decomposed.Offset += ScaledOffset;
565 Scale *= IndexScale.sextOrTrunc(MaxPointerSize);
566 }
567
568 // If we already had an occurrence of this index variable, merge this
569 // scale into it. For example, we want to handle:
570 // A[x][x] -> x*16 + x*4 -> x*20
571 // This also ensures that 'x' only appears in the index list once.
572 for (unsigned i = 0, e = Decomposed.VarIndices.size(); i != e; ++i) {
573 if (Decomposed.VarIndices[i].V == Index &&
574 Decomposed.VarIndices[i].ZExtBits == ZExtBits &&
575 Decomposed.VarIndices[i].SExtBits == SExtBits) {
576 Scale += Decomposed.VarIndices[i].Scale;
577 Decomposed.VarIndices.erase(Decomposed.VarIndices.begin() + i);
578 break;
579 }
580 }
581
582 // Make sure that we have a scale that makes sense for this target's
583 // pointer size.
584 Scale = adjustToPointerSize(Scale, PointerSize);
585
586 if (!!Scale) {
587 VariableGEPIndex Entry = {Index, ZExtBits, SExtBits, Scale};
588 Decomposed.VarIndices.push_back(Entry);
589 }
590 }
591
592 // Take care of wrap-arounds
593 if (GepHasConstantOffset)
594 Decomposed.Offset = adjustToPointerSize(Decomposed.Offset, PointerSize);
595
596 // Analyze the base pointer next.
597 V = GEPOp->getOperand(0);
598 } while (--MaxLookup);
599
600 // If the chain of expressions is too deep, just return early.
601 Decomposed.Base = V;
602 SearchLimitReached++;
603 return Decomposed;
604}
605
606/// Returns whether the given pointer value points to memory that is local to
607/// the function, with global constants being considered local to all
608/// functions.
609bool BasicAAResult::pointsToConstantMemory(const MemoryLocation &Loc,
610 AAQueryInfo &AAQI, bool OrLocal) {
611 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~++20201129111111+e987fbdd85d/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 611, __PRETTY_FUNCTION__))
;
612
613 unsigned MaxLookup = 8;
614 SmallVector<const Value *, 16> Worklist;
615 Worklist.push_back(Loc.Ptr);
616 do {
617 const Value *V = getUnderlyingObject(Worklist.pop_back_val());
618 if (!Visited.insert(V).second) {
619 Visited.clear();
620 return AAResultBase::pointsToConstantMemory(Loc, AAQI, OrLocal);
621 }
622
623 // An alloca instruction defines local memory.
624 if (OrLocal && isa<AllocaInst>(V))
625 continue;
626
627 // A global constant counts as local memory for our purposes.
628 if (const GlobalVariable *GV = dyn_cast<GlobalVariable>(V)) {
629 // Note: this doesn't require GV to be "ODR" because it isn't legal for a
630 // global to be marked constant in some modules and non-constant in
631 // others. GV may even be a declaration, not a definition.
632 if (!GV->isConstant()) {
633 Visited.clear();
634 return AAResultBase::pointsToConstantMemory(Loc, AAQI, OrLocal);
635 }
636 continue;
637 }
638
639 // If both select values point to local memory, then so does the select.
640 if (const SelectInst *SI = dyn_cast<SelectInst>(V)) {
641 Worklist.push_back(SI->getTrueValue());
642 Worklist.push_back(SI->getFalseValue());
643 continue;
644 }
645
646 // If all values incoming to a phi node point to local memory, then so does
647 // the phi.
648 if (const PHINode *PN = dyn_cast<PHINode>(V)) {
649 // Don't bother inspecting phi nodes with many operands.
650 if (PN->getNumIncomingValues() > MaxLookup) {
651 Visited.clear();
652 return AAResultBase::pointsToConstantMemory(Loc, AAQI, OrLocal);
653 }
654 for (Value *IncValue : PN->incoming_values())
655 Worklist.push_back(IncValue);
656 continue;
657 }
658
659 // Otherwise be conservative.
660 Visited.clear();
661 return AAResultBase::pointsToConstantMemory(Loc, AAQI, OrLocal);
662 } while (!Worklist.empty() && --MaxLookup);
663
664 Visited.clear();
665 return Worklist.empty();
666}
667
668/// Returns the behavior when calling the given call site.
669FunctionModRefBehavior BasicAAResult::getModRefBehavior(const CallBase *Call) {
670 if (Call->doesNotAccessMemory())
671 // Can't do better than this.
672 return FMRB_DoesNotAccessMemory;
673
674 FunctionModRefBehavior Min = FMRB_UnknownModRefBehavior;
675
676 // If the callsite knows it only reads memory, don't return worse
677 // than that.
678 if (Call->onlyReadsMemory())
679 Min = FMRB_OnlyReadsMemory;
680 else if (Call->doesNotReadMemory())
681 Min = FMRB_OnlyWritesMemory;
682
683 if (Call->onlyAccessesArgMemory())
684 Min = FunctionModRefBehavior(Min & FMRB_OnlyAccessesArgumentPointees);
685 else if (Call->onlyAccessesInaccessibleMemory())
686 Min = FunctionModRefBehavior(Min & FMRB_OnlyAccessesInaccessibleMem);
687 else if (Call->onlyAccessesInaccessibleMemOrArgMem())
688 Min = FunctionModRefBehavior(Min & FMRB_OnlyAccessesInaccessibleOrArgMem);
689
690 // If the call has operand bundles then aliasing attributes from the function
691 // it calls do not directly apply to the call. This can be made more precise
692 // in the future.
693 if (!Call->hasOperandBundles())
694 if (const Function *F = Call->getCalledFunction())
695 Min =
696 FunctionModRefBehavior(Min & getBestAAResults().getModRefBehavior(F));
697
698 return Min;
699}
700
701/// Returns the behavior when calling the given function. For use when the call
702/// site is not known.
703FunctionModRefBehavior BasicAAResult::getModRefBehavior(const Function *F) {
704 // If the function declares it doesn't access memory, we can't do better.
705 if (F->doesNotAccessMemory())
706 return FMRB_DoesNotAccessMemory;
707
708 FunctionModRefBehavior Min = FMRB_UnknownModRefBehavior;
709
710 // If the function declares it only reads memory, go with that.
711 if (F->onlyReadsMemory())
712 Min = FMRB_OnlyReadsMemory;
713 else if (F->doesNotReadMemory())
714 Min = FMRB_OnlyWritesMemory;
715
716 if (F->onlyAccessesArgMemory())
717 Min = FunctionModRefBehavior(Min & FMRB_OnlyAccessesArgumentPointees);
718 else if (F->onlyAccessesInaccessibleMemory())
719 Min = FunctionModRefBehavior(Min & FMRB_OnlyAccessesInaccessibleMem);
720 else if (F->onlyAccessesInaccessibleMemOrArgMem())
721 Min = FunctionModRefBehavior(Min & FMRB_OnlyAccessesInaccessibleOrArgMem);
722
723 return Min;
724}
725
726/// Returns true if this is a writeonly (i.e Mod only) parameter.
727static bool isWriteOnlyParam(const CallBase *Call, unsigned ArgIdx,
728 const TargetLibraryInfo &TLI) {
729 if (Call->paramHasAttr(ArgIdx, Attribute::WriteOnly))
730 return true;
731
732 // We can bound the aliasing properties of memset_pattern16 just as we can
733 // for memcpy/memset. This is particularly important because the
734 // LoopIdiomRecognizer likes to turn loops into calls to memset_pattern16
735 // whenever possible.
736 // FIXME Consider handling this in InferFunctionAttr.cpp together with other
737 // attributes.
738 LibFunc F;
739 if (Call->getCalledFunction() &&
740 TLI.getLibFunc(*Call->getCalledFunction(), F) &&
741 F == LibFunc_memset_pattern16 && TLI.has(F))
742 if (ArgIdx == 0)
743 return true;
744
745 // TODO: memset_pattern4, memset_pattern8
746 // TODO: _chk variants
747 // TODO: strcmp, strcpy
748
749 return false;
750}
751
752ModRefInfo BasicAAResult::getArgModRefInfo(const CallBase *Call,
753 unsigned ArgIdx) {
754 // Checking for known builtin intrinsics and target library functions.
755 if (isWriteOnlyParam(Call, ArgIdx, TLI))
756 return ModRefInfo::Mod;
757
758 if (Call->paramHasAttr(ArgIdx, Attribute::ReadOnly))
759 return ModRefInfo::Ref;
760
761 if (Call->paramHasAttr(ArgIdx, Attribute::ReadNone))
762 return ModRefInfo::NoModRef;
763
764 return AAResultBase::getArgModRefInfo(Call, ArgIdx);
765}
766
767static bool isIntrinsicCall(const CallBase *Call, Intrinsic::ID IID) {
768 const IntrinsicInst *II = dyn_cast<IntrinsicInst>(Call);
769 return II && II->getIntrinsicID() == IID;
770}
771
772#ifndef NDEBUG
773static const Function *getParent(const Value *V) {
774 if (const Instruction *inst = dyn_cast<Instruction>(V)) {
775 if (!inst->getParent())
776 return nullptr;
777 return inst->getParent()->getParent();
778 }
779
780 if (const Argument *arg = dyn_cast<Argument>(V))
781 return arg->getParent();
782
783 return nullptr;
784}
785
786static bool notDifferentParent(const Value *O1, const Value *O2) {
787
788 const Function *F1 = getParent(O1);
789 const Function *F2 = getParent(O2);
790
791 return !F1 || !F2 || F1 == F2;
792}
793#endif
794
795AliasResult BasicAAResult::alias(const MemoryLocation &LocA,
796 const MemoryLocation &LocB,
797 AAQueryInfo &AAQI) {
798 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~++20201129111111+e987fbdd85d/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 799, __PRETTY_FUNCTION__))
799 "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~++20201129111111+e987fbdd85d/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 799, __PRETTY_FUNCTION__))
;
800
801 // If we have a directly cached entry for these locations, we have recursed
802 // through this once, so just return the cached results. Notably, when this
803 // happens, we don't clear the cache.
804 AAQueryInfo::LocPair Locs(LocA, LocB);
805 if (Locs.first.Ptr > Locs.second.Ptr)
806 std::swap(Locs.first, Locs.second);
807 auto CacheIt = AAQI.AliasCache.find(Locs);
808 if (CacheIt != AAQI.AliasCache.end())
809 return CacheIt->second;
810
811 AliasResult Alias = aliasCheck(LocA.Ptr, LocA.Size, LocA.AATags, LocB.Ptr,
812 LocB.Size, LocB.AATags, AAQI);
813
814 assert(VisitedPhiBBs.empty())((VisitedPhiBBs.empty()) ? static_cast<void> (0) : __assert_fail
("VisitedPhiBBs.empty()", "/build/llvm-toolchain-snapshot-12~++20201129111111+e987fbdd85d/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 814, __PRETTY_FUNCTION__))
;
815 return Alias;
816}
817
818/// Checks to see if the specified callsite can clobber the specified memory
819/// object.
820///
821/// Since we only look at local properties of this function, we really can't
822/// say much about this query. We do, however, use simple "address taken"
823/// analysis on local objects.
824ModRefInfo BasicAAResult::getModRefInfo(const CallBase *Call,
825 const MemoryLocation &Loc,
826 AAQueryInfo &AAQI) {
827 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~++20201129111111+e987fbdd85d/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 828, __PRETTY_FUNCTION__))
828 "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~++20201129111111+e987fbdd85d/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 828, __PRETTY_FUNCTION__))
;
829
830 const Value *Object = getUnderlyingObject(Loc.Ptr);
831
832 // Calls marked 'tail' cannot read or write allocas from the current frame
833 // because the current frame might be destroyed by the time they run. However,
834 // a tail call may use an alloca with byval. Calling with byval copies the
835 // contents of the alloca into argument registers or stack slots, so there is
836 // no lifetime issue.
837 if (isa<AllocaInst>(Object))
838 if (const CallInst *CI = dyn_cast<CallInst>(Call))
839 if (CI->isTailCall() &&
840 !CI->getAttributes().hasAttrSomewhere(Attribute::ByVal))
841 return ModRefInfo::NoModRef;
842
843 // Stack restore is able to modify unescaped dynamic allocas. Assume it may
844 // modify them even though the alloca is not escaped.
845 if (auto *AI = dyn_cast<AllocaInst>(Object))
846 if (!AI->isStaticAlloca() && isIntrinsicCall(Call, Intrinsic::stackrestore))
847 return ModRefInfo::Mod;
848
849 // If the pointer is to a locally allocated object that does not escape,
850 // then the call can not mod/ref the pointer unless the call takes the pointer
851 // as an argument, and itself doesn't capture it.
852 if (!isa<Constant>(Object) && Call != Object &&
853 isNonEscapingLocalObject(Object, &AAQI.IsCapturedCache)) {
854
855 // Optimistically assume that call doesn't touch Object and check this
856 // assumption in the following loop.
857 ModRefInfo Result = ModRefInfo::NoModRef;
858 bool IsMustAlias = true;
859
860 unsigned OperandNo = 0;
861 for (auto CI = Call->data_operands_begin(), CE = Call->data_operands_end();
862 CI != CE; ++CI, ++OperandNo) {
863 // Only look at the no-capture or byval pointer arguments. If this
864 // pointer were passed to arguments that were neither of these, then it
865 // couldn't be no-capture.
866 if (!(*CI)->getType()->isPointerTy() ||
867 (!Call->doesNotCapture(OperandNo) &&
868 OperandNo < Call->getNumArgOperands() &&
869 !Call->isByValArgument(OperandNo)))
870 continue;
871
872 // Call doesn't access memory through this operand, so we don't care
873 // if it aliases with Object.
874 if (Call->doesNotAccessMemory(OperandNo))
875 continue;
876
877 // If this is a no-capture pointer argument, see if we can tell that it
878 // is impossible to alias the pointer we're checking.
879 AliasResult AR = getBestAAResults().alias(
880 MemoryLocation::getBeforeOrAfter(*CI),
881 MemoryLocation::getBeforeOrAfter(Object), AAQI);
882 if (AR != MustAlias)
883 IsMustAlias = false;
884 // Operand doesn't alias 'Object', continue looking for other aliases
885 if (AR == NoAlias)
886 continue;
887 // Operand aliases 'Object', but call doesn't modify it. Strengthen
888 // initial assumption and keep looking in case if there are more aliases.
889 if (Call->onlyReadsMemory(OperandNo)) {
890 Result = setRef(Result);
891 continue;
892 }
893 // Operand aliases 'Object' but call only writes into it.
894 if (Call->doesNotReadMemory(OperandNo)) {
895 Result = setMod(Result);
896 continue;
897 }
898 // This operand aliases 'Object' and call reads and writes into it.
899 // Setting ModRef will not yield an early return below, MustAlias is not
900 // used further.
901 Result = ModRefInfo::ModRef;
902 break;
903 }
904
905 // No operand aliases, reset Must bit. Add below if at least one aliases
906 // and all aliases found are MustAlias.
907 if (isNoModRef(Result))
908 IsMustAlias = false;
909
910 // Early return if we improved mod ref information
911 if (!isModAndRefSet(Result)) {
912 if (isNoModRef(Result))
913 return ModRefInfo::NoModRef;
914 return IsMustAlias ? setMust(Result) : clearMust(Result);
915 }
916 }
917
918 // If the call is malloc/calloc like, we can assume that it doesn't
919 // modify any IR visible value. This is only valid because we assume these
920 // routines do not read values visible in the IR. TODO: Consider special
921 // casing realloc and strdup routines which access only their arguments as
922 // well. Or alternatively, replace all of this with inaccessiblememonly once
923 // that's implemented fully.
924 if (isMallocOrCallocLikeFn(Call, &TLI)) {
925 // Be conservative if the accessed pointer may alias the allocation -
926 // fallback to the generic handling below.
927 if (getBestAAResults().alias(MemoryLocation::getBeforeOrAfter(Call),
928 Loc, AAQI) == NoAlias)
929 return ModRefInfo::NoModRef;
930 }
931
932 // The semantics of memcpy intrinsics either exactly overlap or do not
933 // overlap, i.e., source and destination of any given memcpy are either
934 // no-alias or must-alias.
935 if (auto *Inst = dyn_cast<AnyMemCpyInst>(Call)) {
936 AliasResult SrcAA =
937 getBestAAResults().alias(MemoryLocation::getForSource(Inst), Loc, AAQI);
938 AliasResult DestAA =
939 getBestAAResults().alias(MemoryLocation::getForDest(Inst), Loc, AAQI);
940 // It's also possible for Loc to alias both src and dest, or neither.
941 ModRefInfo rv = ModRefInfo::NoModRef;
942 if (SrcAA != NoAlias)
943 rv = setRef(rv);
944 if (DestAA != NoAlias)
945 rv = setMod(rv);
946 return rv;
947 }
948
949 // While the assume intrinsic is marked as arbitrarily writing so that
950 // proper control dependencies will be maintained, it never aliases any
951 // particular memory location.
952 if (isIntrinsicCall(Call, Intrinsic::assume))
953 return ModRefInfo::NoModRef;
954
955 // Like assumes, guard intrinsics are also marked as arbitrarily writing so
956 // that proper control dependencies are maintained but they never mods any
957 // particular memory location.
958 //
959 // *Unlike* assumes, guard intrinsics are modeled as reading memory since the
960 // heap state at the point the guard is issued needs to be consistent in case
961 // the guard invokes the "deopt" continuation.
962 if (isIntrinsicCall(Call, Intrinsic::experimental_guard))
963 return ModRefInfo::Ref;
964 // The same applies to deoptimize which is essentially a guard(false).
965 if (isIntrinsicCall(Call, Intrinsic::experimental_deoptimize))
966 return ModRefInfo::Ref;
967
968 // Like assumes, invariant.start intrinsics were also marked as arbitrarily
969 // writing so that proper control dependencies are maintained but they never
970 // mod any particular memory location visible to the IR.
971 // *Unlike* assumes (which are now modeled as NoModRef), invariant.start
972 // intrinsic is now modeled as reading memory. This prevents hoisting the
973 // invariant.start intrinsic over stores. Consider:
974 // *ptr = 40;
975 // *ptr = 50;
976 // invariant_start(ptr)
977 // int val = *ptr;
978 // print(val);
979 //
980 // This cannot be transformed to:
981 //
982 // *ptr = 40;
983 // invariant_start(ptr)
984 // *ptr = 50;
985 // int val = *ptr;
986 // print(val);
987 //
988 // The transformation will cause the second store to be ignored (based on
989 // rules of invariant.start) and print 40, while the first program always
990 // prints 50.
991 if (isIntrinsicCall(Call, Intrinsic::invariant_start))
992 return ModRefInfo::Ref;
993
994 // The AAResultBase base class has some smarts, lets use them.
995 return AAResultBase::getModRefInfo(Call, Loc, AAQI);
996}
997
998ModRefInfo BasicAAResult::getModRefInfo(const CallBase *Call1,
999 const CallBase *Call2,
1000 AAQueryInfo &AAQI) {
1001 // While the assume intrinsic is marked as arbitrarily writing so that
1002 // proper control dependencies will be maintained, it never aliases any
1003 // particular memory location.
1004 if (isIntrinsicCall(Call1, Intrinsic::assume) ||
1005 isIntrinsicCall(Call2, Intrinsic::assume))
1006 return ModRefInfo::NoModRef;
1007
1008 // Like assumes, guard intrinsics are also marked as arbitrarily writing so
1009 // that proper control dependencies are maintained but they never mod any
1010 // particular memory location.
1011 //
1012 // *Unlike* assumes, guard intrinsics are modeled as reading memory since the
1013 // heap state at the point the guard is issued needs to be consistent in case
1014 // the guard invokes the "deopt" continuation.
1015
1016 // NB! This function is *not* commutative, so we special case two
1017 // possibilities for guard intrinsics.
1018
1019 if (isIntrinsicCall(Call1, Intrinsic::experimental_guard))
1020 return isModSet(createModRefInfo(getModRefBehavior(Call2)))
1021 ? ModRefInfo::Ref
1022 : ModRefInfo::NoModRef;
1023
1024 if (isIntrinsicCall(Call2, Intrinsic::experimental_guard))
1025 return isModSet(createModRefInfo(getModRefBehavior(Call1)))
1026 ? ModRefInfo::Mod
1027 : ModRefInfo::NoModRef;
1028
1029 // The AAResultBase base class has some smarts, lets use them.
1030 return AAResultBase::getModRefInfo(Call1, Call2, AAQI);
1031}
1032
1033/// Provide ad-hoc rules to disambiguate accesses through two GEP operators,
1034/// both having the exact same pointer operand.
1035static AliasResult aliasSameBasePointerGEPs(const GEPOperator *GEP1,
1036 LocationSize MaybeV1Size,
1037 const GEPOperator *GEP2,
1038 LocationSize MaybeV2Size,
1039 const DataLayout &DL) {
1040 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~++20201129111111+e987fbdd85d/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1043, __PRETTY_FUNCTION__))
1041 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~++20201129111111+e987fbdd85d/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1043, __PRETTY_FUNCTION__))
1042 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~++20201129111111+e987fbdd85d/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1043, __PRETTY_FUNCTION__))
1043 "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~++20201129111111+e987fbdd85d/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1043, __PRETTY_FUNCTION__))
;
1044
1045 // Try to determine whether GEP1 and GEP2 index through arrays, into structs,
1046 // such that the struct field accesses provably cannot alias.
1047 // We also need at least two indices (the pointer, and the struct field).
1048 if (GEP1->getNumIndices() != GEP2->getNumIndices() ||
1049 GEP1->getNumIndices() < 2)
1050 return MayAlias;
1051
1052 // If we don't know the size of the accesses through both GEPs, we can't
1053 // determine whether the struct fields accessed can't alias.
1054 if (!MaybeV1Size.hasValue() || !MaybeV2Size.hasValue())
1055 return MayAlias;
1056
1057 const uint64_t V1Size = MaybeV1Size.getValue();
1058 const uint64_t V2Size = MaybeV2Size.getValue();
1059
1060 ConstantInt *C1 =
1061 dyn_cast<ConstantInt>(GEP1->getOperand(GEP1->getNumOperands() - 1));
1062 ConstantInt *C2 =
1063 dyn_cast<ConstantInt>(GEP2->getOperand(GEP2->getNumOperands() - 1));
1064
1065 // If the last (struct) indices are constants and are equal, the other indices
1066 // might be also be dynamically equal, so the GEPs can alias.
1067 if (C1 && C2) {
1068 unsigned BitWidth = std::max(C1->getBitWidth(), C2->getBitWidth());
1069 if (C1->getValue().sextOrSelf(BitWidth) ==
1070 C2->getValue().sextOrSelf(BitWidth))
1071 return MayAlias;
1072 }
1073
1074 // Find the last-indexed type of the GEP, i.e., the type you'd get if
1075 // you stripped the last index.
1076 // On the way, look at each indexed type. If there's something other
1077 // than an array, different indices can lead to different final types.
1078 SmallVector<Value *, 8> IntermediateIndices;
1079
1080 // Insert the first index; we don't need to check the type indexed
1081 // through it as it only drops the pointer indirection.
1082 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~++20201129111111+e987fbdd85d/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1082, __PRETTY_FUNCTION__))
;
1083 IntermediateIndices.push_back(GEP1->getOperand(1));
1084
1085 // Insert all the remaining indices but the last one.
1086 // Also, check that they all index through arrays.
1087 for (unsigned i = 1, e = GEP1->getNumIndices() - 1; i != e; ++i) {
1088 if (!isa<ArrayType>(GetElementPtrInst::getIndexedType(
1089 GEP1->getSourceElementType(), IntermediateIndices)))
1090 return MayAlias;
1091 IntermediateIndices.push_back(GEP1->getOperand(i + 1));
1092 }
1093
1094 auto *Ty = GetElementPtrInst::getIndexedType(
1095 GEP1->getSourceElementType(), IntermediateIndices);
1096 if (isa<ArrayType>(Ty) || isa<VectorType>(Ty)) {
1097 // We know that:
1098 // - both GEPs begin indexing from the exact same pointer;
1099 // - the last indices in both GEPs are constants, indexing into a sequential
1100 // type (array or vector);
1101 // - both GEPs only index through arrays prior to that.
1102 //
1103 // Because array indices greater than the number of elements are valid in
1104 // GEPs, unless we know the intermediate indices are identical between
1105 // GEP1 and GEP2 we cannot guarantee that the last indexed arrays don't
1106 // partially overlap. We also need to check that the loaded size matches
1107 // the element size, otherwise we could still have overlap.
1108 Type *LastElementTy = GetElementPtrInst::getTypeAtIndex(Ty, (uint64_t)0);
1109 const uint64_t ElementSize =
1110 DL.getTypeStoreSize(LastElementTy).getFixedSize();
1111 if (V1Size != ElementSize || V2Size != ElementSize)
1112 return MayAlias;
1113
1114 for (unsigned i = 0, e = GEP1->getNumIndices() - 1; i != e; ++i)
1115 if (GEP1->getOperand(i + 1) != GEP2->getOperand(i + 1))
1116 return MayAlias;
1117
1118 // Now we know that the array/pointer that GEP1 indexes into and that
1119 // that GEP2 indexes into must either precisely overlap or be disjoint.
1120 // Because they cannot partially overlap and because fields in an array
1121 // cannot overlap, if we can prove the final indices are different between
1122 // GEP1 and GEP2, we can conclude GEP1 and GEP2 don't alias.
1123
1124 // If the last indices are constants, we've already checked they don't
1125 // equal each other so we can exit early.
1126 if (C1 && C2)
1127 return NoAlias;
1128 {
1129 Value *GEP1LastIdx = GEP1->getOperand(GEP1->getNumOperands() - 1);
1130 Value *GEP2LastIdx = GEP2->getOperand(GEP2->getNumOperands() - 1);
1131 if (isa<PHINode>(GEP1LastIdx) || isa<PHINode>(GEP2LastIdx)) {
1132 // If one of the indices is a PHI node, be safe and only use
1133 // computeKnownBits so we don't make any assumptions about the
1134 // relationships between the two indices. This is important if we're
1135 // asking about values from different loop iterations. See PR32314.
1136 // TODO: We may be able to change the check so we only do this when
1137 // we definitely looked through a PHINode.
1138 if (GEP1LastIdx != GEP2LastIdx &&
1139 GEP1LastIdx->getType() == GEP2LastIdx->getType()) {
1140 KnownBits Known1 = computeKnownBits(GEP1LastIdx, DL);
1141 KnownBits Known2 = computeKnownBits(GEP2LastIdx, DL);
1142 if (Known1.Zero.intersects(Known2.One) ||
1143 Known1.One.intersects(Known2.Zero))
1144 return NoAlias;
1145 }
1146 } else if (isKnownNonEqual(GEP1LastIdx, GEP2LastIdx, DL))
1147 return NoAlias;
1148 }
1149 }
1150 return MayAlias;
1151}
1152
1153// If a we have (a) a GEP and (b) a pointer based on an alloca, and the
1154// beginning of the object the GEP points would have a negative offset with
1155// repsect to the alloca, that means the GEP can not alias pointer (b).
1156// Note that the pointer based on the alloca may not be a GEP. For
1157// example, it may be the alloca itself.
1158// The same applies if (b) is based on a GlobalVariable. Note that just being
1159// based on isIdentifiedObject() is not enough - we need an identified object
1160// that does not permit access to negative offsets. For example, a negative
1161// offset from a noalias argument or call can be inbounds w.r.t the actual
1162// underlying object.
1163//
1164// For example, consider:
1165//
1166// struct { int f0, int f1, ...} foo;
1167// foo alloca;
1168// foo* random = bar(alloca);
1169// int *f0 = &alloca.f0
1170// int *f1 = &random->f1;
1171//
1172// Which is lowered, approximately, to:
1173//
1174// %alloca = alloca %struct.foo
1175// %random = call %struct.foo* @random(%struct.foo* %alloca)
1176// %f0 = getelementptr inbounds %struct, %struct.foo* %alloca, i32 0, i32 0
1177// %f1 = getelementptr inbounds %struct, %struct.foo* %random, i32 0, i32 1
1178//
1179// Assume %f1 and %f0 alias. Then %f1 would point into the object allocated
1180// by %alloca. Since the %f1 GEP is inbounds, that means %random must also
1181// point into the same object. But since %f0 points to the beginning of %alloca,
1182// the highest %f1 can be is (%alloca + 3). This means %random can not be higher
1183// than (%alloca - 1), and so is not inbounds, a contradiction.
1184bool BasicAAResult::isGEPBaseAtNegativeOffset(const GEPOperator *GEPOp,
1185 const DecomposedGEP &DecompGEP, const DecomposedGEP &DecompObject,
1186 LocationSize MaybeObjectAccessSize) {
1187 // If the object access size is unknown, or the GEP isn't inbounds, bail.
1188 if (!MaybeObjectAccessSize.hasValue() || !GEPOp->isInBounds())
1189 return false;
1190
1191 const uint64_t ObjectAccessSize = MaybeObjectAccessSize.getValue();
1192
1193 // We need the object to be an alloca or a globalvariable, and want to know
1194 // the offset of the pointer from the object precisely, so no variable
1195 // indices are allowed.
1196 if (!(isa<AllocaInst>(DecompObject.Base) ||
1197 isa<GlobalVariable>(DecompObject.Base)) ||
1198 !DecompObject.VarIndices.empty())
1199 return false;
1200
1201 // If the GEP has no variable indices, we know the precise offset
1202 // from the base, then use it. If the GEP has variable indices,
1203 // we can't get exact GEP offset to identify pointer alias. So return
1204 // false in that case.
1205 if (!DecompGEP.VarIndices.empty())
1206 return false;
1207
1208 return DecompGEP.Offset.sge(DecompObject.Offset + (int64_t)ObjectAccessSize);
1209}
1210
1211/// Provides a bunch of ad-hoc rules to disambiguate a GEP instruction against
1212/// another pointer.
1213///
1214/// We know that V1 is a GEP, but we don't know anything about V2.
1215/// UnderlyingV1 is getUnderlyingObject(GEP1), UnderlyingV2 is the same for
1216/// V2.
1217AliasResult BasicAAResult::aliasGEP(
1218 const GEPOperator *GEP1, LocationSize V1Size, const AAMDNodes &V1AAInfo,
1219 const Value *V2, LocationSize V2Size, const AAMDNodes &V2AAInfo,
1220 const Value *UnderlyingV1, const Value *UnderlyingV2, AAQueryInfo &AAQI) {
1221 DecomposedGEP DecompGEP1 = DecomposeGEPExpression(GEP1, DL, &AC, DT);
1222 DecomposedGEP DecompGEP2 = DecomposeGEPExpression(V2, DL, &AC, DT);
1223
1224 // Don't attempt to analyze the decomposed GEP if index scale is not a
1225 // compile-time constant.
1226 if (!DecompGEP1.HasCompileTimeConstantScale ||
1227 !DecompGEP2.HasCompileTimeConstantScale)
1228 return MayAlias;
1229
1230 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~++20201129111111+e987fbdd85d/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1232, __PRETTY_FUNCTION__))
1231 "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~++20201129111111+e987fbdd85d/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1232, __PRETTY_FUNCTION__))
1232 "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~++20201129111111+e987fbdd85d/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1232, __PRETTY_FUNCTION__))
;
1233
1234 // If the GEP's offset relative to its base is such that the base would
1235 // fall below the start of the object underlying V2, then the GEP and V2
1236 // cannot alias.
1237 if (isGEPBaseAtNegativeOffset(GEP1, DecompGEP1, DecompGEP2, V2Size))
1238 return NoAlias;
1239 // If we have two gep instructions with must-alias or not-alias'ing base
1240 // pointers, figure out if the indexes to the GEP tell us anything about the
1241 // derived pointer.
1242 if (const GEPOperator *GEP2 = dyn_cast<GEPOperator>(V2)) {
1243 // Check for the GEP base being at a negative offset, this time in the other
1244 // direction.
1245 if (isGEPBaseAtNegativeOffset(GEP2, DecompGEP2, DecompGEP1, V1Size))
1246 return NoAlias;
1247 // Do the base pointers alias?
1248 AliasResult BaseAlias = aliasCheck(
1249 UnderlyingV1, LocationSize::beforeOrAfterPointer(), AAMDNodes(),
1250 UnderlyingV2, LocationSize::beforeOrAfterPointer(), AAMDNodes(), AAQI);
1251
1252 // For GEPs with identical offsets, we can preserve the size and AAInfo
1253 // when performing the alias check on the underlying objects.
1254 if (BaseAlias == MayAlias && DecompGEP1.Offset == DecompGEP2.Offset &&
1255 DecompGEP1.VarIndices == DecompGEP2.VarIndices) {
1256 AliasResult PreciseBaseAlias = aliasCheck(
1257 UnderlyingV1, V1Size, V1AAInfo, UnderlyingV2, V2Size, V2AAInfo, AAQI);
1258 if (PreciseBaseAlias == NoAlias)
1259 return NoAlias;
1260 }
1261
1262 // If we get a No or May, then return it immediately, no amount of analysis
1263 // will improve this situation.
1264 if (BaseAlias != MustAlias) {
1265 assert(BaseAlias == NoAlias || BaseAlias == MayAlias)((BaseAlias == NoAlias || BaseAlias == MayAlias) ? static_cast
<void> (0) : __assert_fail ("BaseAlias == NoAlias || BaseAlias == MayAlias"
, "/build/llvm-toolchain-snapshot-12~++20201129111111+e987fbdd85d/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1265, __PRETTY_FUNCTION__))
;
1266 return BaseAlias;
1267 }
1268
1269 // Otherwise, we have a MustAlias. Since the base pointers alias each other
1270 // exactly, see if the computed offset from the common pointer tells us
1271 // about the relation of the resulting pointer.
1272 // If we know the two GEPs are based off of the exact same pointer (and not
1273 // just the same underlying object), see if that tells us anything about
1274 // the resulting pointers.
1275 if (GEP1->getPointerOperand()->stripPointerCastsAndInvariantGroups() ==
1276 GEP2->getPointerOperand()->stripPointerCastsAndInvariantGroups() &&
1277 GEP1->getPointerOperandType() == GEP2->getPointerOperandType()) {
1278 AliasResult R = aliasSameBasePointerGEPs(GEP1, V1Size, GEP2, V2Size, DL);
1279 // If we couldn't find anything interesting, don't abandon just yet.
1280 if (R != MayAlias)
1281 return R;
1282 }
1283
1284 // Subtract the GEP2 pointer from the GEP1 pointer to find out their
1285 // symbolic difference.
1286 DecompGEP1.Offset -= DecompGEP2.Offset;
1287 GetIndexDifference(DecompGEP1.VarIndices, DecompGEP2.VarIndices);
1288
1289 } else {
1290 // Check to see if these two pointers are related by the getelementptr
1291 // instruction. If one pointer is a GEP with a non-zero index of the other
1292 // pointer, we know they cannot alias.
1293
1294 // If both accesses are unknown size, we can't do anything useful here.
1295 if (!V1Size.hasValue() && !V2Size.hasValue())
1296 return MayAlias;
1297
1298 AliasResult R = aliasCheck(
1299 UnderlyingV1, LocationSize::beforeOrAfterPointer(), AAMDNodes(),
1300 V2, V2Size, V2AAInfo, AAQI, nullptr, UnderlyingV2);
1301 if (R != MustAlias) {
1302 // If V2 may alias GEP base pointer, conservatively returns MayAlias.
1303 // If V2 is known not to alias GEP base pointer, then the two values
1304 // cannot alias per GEP semantics: "Any memory access must be done through
1305 // a pointer value associated with an address range of the memory access,
1306 // otherwise the behavior is undefined.".
1307 assert(R == NoAlias || R == MayAlias)((R == NoAlias || R == MayAlias) ? static_cast<void> (0
) : __assert_fail ("R == NoAlias || R == MayAlias", "/build/llvm-toolchain-snapshot-12~++20201129111111+e987fbdd85d/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1307, __PRETTY_FUNCTION__))
;
1308 return R;
1309 }
1310 }
1311
1312 // In the two GEP Case, if there is no difference in the offsets of the
1313 // computed pointers, the resultant pointers are a must alias. This
1314 // happens when we have two lexically identical GEP's (for example).
1315 //
1316 // In the other case, if we have getelementptr <ptr>, 0, 0, 0, 0, ... and V2
1317 // must aliases the GEP, the end result is a must alias also.
1318 if (DecompGEP1.Offset == 0 && DecompGEP1.VarIndices.empty())
1319 return MustAlias;
1320
1321 // If there is a constant difference between the pointers, but the difference
1322 // is less than the size of the associated memory object, then we know
1323 // that the objects are partially overlapping. If the difference is
1324 // greater, we know they do not overlap.
1325 if (DecompGEP1.Offset != 0 && DecompGEP1.VarIndices.empty()) {
1326 if (DecompGEP1.Offset.sge(0)) {
1327 if (V2Size.hasValue()) {
1328 if (DecompGEP1.Offset.ult(V2Size.getValue()))
1329 return PartialAlias;
1330 return NoAlias;
1331 }
1332 } else {
1333 // We have the situation where:
1334 // + +
1335 // | BaseOffset |
1336 // ---------------->|
1337 // |-->V1Size |-------> V2Size
1338 // GEP1 V2
1339 if (V1Size.hasValue()) {
1340 if ((-DecompGEP1.Offset).ult(V1Size.getValue()))
1341 return PartialAlias;
1342 return NoAlias;
1343 }
1344 }
1345 }
1346
1347 if (!DecompGEP1.VarIndices.empty()) {
1348 APInt GCD;
1349 bool AllNonNegative = DecompGEP1.Offset.isNonNegative();
1350 bool AllNonPositive = DecompGEP1.Offset.isNonPositive();
1351 for (unsigned i = 0, e = DecompGEP1.VarIndices.size(); i != e; ++i) {
1352 const APInt &Scale = DecompGEP1.VarIndices[i].Scale;
1353 if (i == 0)
1354 GCD = Scale.abs();
1355 else
1356 GCD = APIntOps::GreatestCommonDivisor(GCD, Scale.abs());
1357
1358 if (AllNonNegative || AllNonPositive) {
1359 // If the Value could change between cycles, then any reasoning about
1360 // the Value this cycle may not hold in the next cycle. We'll just
1361 // give up if we can't determine conditions that hold for every cycle:
1362 const Value *V = DecompGEP1.VarIndices[i].V;
1363
1364 KnownBits Known =
1365 computeKnownBits(V, DL, 0, &AC, dyn_cast<Instruction>(GEP1), DT);
1366 bool SignKnownZero = Known.isNonNegative();
1367 bool SignKnownOne = Known.isNegative();
1368
1369 // Zero-extension widens the variable, and so forces the sign
1370 // bit to zero.
1371 bool IsZExt = DecompGEP1.VarIndices[i].ZExtBits > 0 || isa<ZExtInst>(V);
1372 SignKnownZero |= IsZExt;
1373 SignKnownOne &= !IsZExt;
1374
1375 AllNonNegative &= (SignKnownZero && Scale.isNonNegative()) ||
1376 (SignKnownOne && Scale.isNonPositive());
1377 AllNonPositive &= (SignKnownZero && Scale.isNonPositive()) ||
1378 (SignKnownOne && Scale.isNonNegative());
1379 }
1380 }
1381
1382 // We now have accesses at two offsets from the same base:
1383 // 1. (...)*GCD + DecompGEP1.Offset with size V1Size
1384 // 2. 0 with size V2Size
1385 // Using arithmetic modulo GCD, the accesses are at
1386 // [ModOffset..ModOffset+V1Size) and [0..V2Size). If the first access fits
1387 // into the range [V2Size..GCD), then we know they cannot overlap.
1388 APInt ModOffset = DecompGEP1.Offset.srem(GCD);
1389 if (ModOffset.isNegative())
1390 ModOffset += GCD; // We want mod, not rem.
1391 if (V1Size.hasValue() && V2Size.hasValue() &&
1392 ModOffset.uge(V2Size.getValue()) &&
1393 (GCD - ModOffset).uge(V1Size.getValue()))
1394 return NoAlias;
1395
1396 // If we know all the variables are non-negative, then the total offset is
1397 // also non-negative and >= DecompGEP1.Offset. We have the following layout:
1398 // [0, V2Size) ... [TotalOffset, TotalOffer+V1Size]
1399 // If DecompGEP1.Offset >= V2Size, the accesses don't alias.
1400 if (AllNonNegative && V2Size.hasValue() &&
1401 DecompGEP1.Offset.uge(V2Size.getValue()))
1402 return NoAlias;
1403 // Similarly, if the variables are non-positive, then the total offset is
1404 // also non-positive and <= DecompGEP1.Offset. We have the following layout:
1405 // [TotalOffset, TotalOffset+V1Size) ... [0, V2Size)
1406 // If -DecompGEP1.Offset >= V1Size, the accesses don't alias.
1407 if (AllNonPositive && V1Size.hasValue() &&
1408 (-DecompGEP1.Offset).uge(V1Size.getValue()))
1409 return NoAlias;
1410
1411 if (constantOffsetHeuristic(DecompGEP1.VarIndices, V1Size, V2Size,
1412 DecompGEP1.Offset, &AC, DT))
1413 return NoAlias;
1414 }
1415
1416 // Statically, we can see that the base objects are the same, but the
1417 // pointers have dynamic offsets which we can't resolve. And none of our
1418 // little tricks above worked.
1419 return MayAlias;
1420}
1421
1422static AliasResult MergeAliasResults(AliasResult A, AliasResult B) {
1423 // If the results agree, take it.
1424 if (A == B)
1425 return A;
1426 // A mix of PartialAlias and MustAlias is PartialAlias.
1427 if ((A == PartialAlias && B == MustAlias) ||
1428 (B == PartialAlias && A == MustAlias))
1429 return PartialAlias;
1430 // Otherwise, we don't know anything.
1431 return MayAlias;
1432}
1433
1434/// Provides a bunch of ad-hoc rules to disambiguate a Select instruction
1435/// against another.
1436AliasResult
1437BasicAAResult::aliasSelect(const SelectInst *SI, LocationSize SISize,
1438 const AAMDNodes &SIAAInfo, const Value *V2,
1439 LocationSize V2Size, const AAMDNodes &V2AAInfo,
1440 const Value *UnderV2, AAQueryInfo &AAQI) {
1441 // If the values are Selects with the same condition, we can do a more precise
1442 // check: just check for aliases between the values on corresponding arms.
1443 if (const SelectInst *SI2 = dyn_cast<SelectInst>(V2))
1444 if (SI->getCondition() == SI2->getCondition()) {
1445 AliasResult Alias =
1446 aliasCheck(SI->getTrueValue(), SISize, SIAAInfo, SI2->getTrueValue(),
1447 V2Size, V2AAInfo, AAQI);
1448 if (Alias == MayAlias)
1449 return MayAlias;
1450 AliasResult ThisAlias =
1451 aliasCheck(SI->getFalseValue(), SISize, SIAAInfo,
1452 SI2->getFalseValue(), V2Size, V2AAInfo, AAQI);
1453 return MergeAliasResults(ThisAlias, Alias);
1454 }
1455
1456 // If both arms of the Select node NoAlias or MustAlias V2, then returns
1457 // NoAlias / MustAlias. Otherwise, returns MayAlias.
1458 AliasResult Alias = aliasCheck(V2, V2Size, V2AAInfo, SI->getTrueValue(),
1459 SISize, SIAAInfo, AAQI, UnderV2);
1460 if (Alias == MayAlias)
1461 return MayAlias;
1462
1463 AliasResult ThisAlias = aliasCheck(V2, V2Size, V2AAInfo, SI->getFalseValue(),
1464 SISize, SIAAInfo, AAQI, UnderV2);
1465 return MergeAliasResults(ThisAlias, Alias);
1466}
1467
1468/// Provide a bunch of ad-hoc rules to disambiguate a PHI instruction against
1469/// another.
1470AliasResult BasicAAResult::aliasPHI(const PHINode *PN, LocationSize PNSize,
1471 const AAMDNodes &PNAAInfo, const Value *V2,
1472 LocationSize V2Size,
1473 const AAMDNodes &V2AAInfo,
1474 const Value *UnderV2, AAQueryInfo &AAQI) {
1475 // If the values are PHIs in the same block, we can do a more precise
1476 // as well as efficient check: just check for aliases between the values
1477 // on corresponding edges.
1478 if (const PHINode *PN2 = dyn_cast<PHINode>(V2))
1479 if (PN2->getParent() == PN->getParent()) {
1480 AAQueryInfo::LocPair Locs(MemoryLocation(PN, PNSize, PNAAInfo),
1481 MemoryLocation(V2, V2Size, V2AAInfo));
1482 if (PN > V2)
1483 std::swap(Locs.first, Locs.second);
1484 // Analyse the PHIs' inputs under the assumption that the PHIs are
1485 // NoAlias.
1486 // If the PHIs are May/MustAlias there must be (recursively) an input
1487 // operand from outside the PHIs' cycle that is MayAlias/MustAlias or
1488 // there must be an operation on the PHIs within the PHIs' value cycle
1489 // that causes a MayAlias.
1490 // Pretend the phis do not alias.
1491 AliasResult Alias = NoAlias;
1492 AliasResult OrigAliasResult;
1493 {
1494 // Limited lifetime iterator invalidated by the aliasCheck call below.
1495 auto CacheIt = AAQI.AliasCache.find(Locs);
1496 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~++20201129111111+e987fbdd85d/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1497, __PRETTY_FUNCTION__))
1497 "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~++20201129111111+e987fbdd85d/llvm/lib/Analysis/BasicAliasAnalysis.cpp"
, 1497, __PRETTY_FUNCTION__))
;
1498 OrigAliasResult = CacheIt->second;
1499 CacheIt->second = NoAlias;
1500 }
1501
1502 for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i) {
1503 AliasResult ThisAlias =
1504 aliasCheck(PN->getIncomingValue(i), PNSize, PNAAInfo,
1505 PN2->getIncomingValueForBlock(PN->getIncomingBlock(i)),
1506 V2Size, V2AAInfo, AAQI);
1507 Alias = MergeAliasResults(ThisAlias, Alias);
1508 if (Alias == MayAlias)
1509 break;
1510 }
1511
1512 // Reset if speculation failed.
1513 if (Alias != NoAlias)
1514 AAQI.updateResult(Locs, OrigAliasResult);
1515 return Alias;
1516 }
1517
1518 SmallVector<Value *, 4> V1Srcs;
1519 // If a phi operand recurses back to the phi, we can still determine NoAlias
1520 // if we don't alias the underlying objects of the other phi operands, as we
1521 // know that the recursive phi needs to be based on them in some way.
1522 bool isRecursive = false;
1523 auto CheckForRecPhi = [&](Value *PV) {
1524 if (!EnableRecPhiAnalysis)
1525 return false;
1526 if (getUnderlyingObject(PV) == PN) {
1527 isRecursive = true;
1528 return true;
1529 }
1530 return false;
1531 };
1532
1533 if (PV) {
1534 // If we have PhiValues then use it to get the underlying phi values.
1535 const PhiValues::ValueSet &PhiValueSet = PV->getValuesForPhi(PN);
1536 // If we have more phi values than the search depth then return MayAlias
1537 // conservatively to avoid compile time explosion. The worst possible case
1538 // is if both sides are PHI nodes. In which case, this is O(m x n) time
1539 // where 'm' and 'n' are the number of PHI sources.
1540 if (PhiValueSet.size() > MaxLookupSearchDepth)
1541 return MayAlias;
1542 // Add the values to V1Srcs
1543 for (Value *PV1 : PhiValueSet) {
1544 if (CheckForRecPhi(PV1))
1545 continue;
1546 V1Srcs.push_back(PV1);
1547 }
1548 } else {
1549 // If we don't have PhiInfo then just look at the operands of the phi itself
1550 // FIXME: Remove this once we can guarantee that we have PhiInfo always
1551 SmallPtrSet<Value *, 4> UniqueSrc;
1552 for (Value *PV1 : PN->incoming_values()) {
1553 if (isa<PHINode>(PV1))
1554 // If any of the source itself is a PHI, return MayAlias conservatively
1555 // to avoid compile time explosion. The worst possible case is if both
1556 // sides are PHI nodes. In which case, this is O(m x n) time where 'm'
1557 // and 'n' are the number of PHI sources.
1558 return MayAlias;
1559
1560 if (CheckForRecPhi(PV1))
1561 continue;
1562
1563 if (UniqueSrc.insert(PV1).second)
1564 V1Srcs.push_back(PV1);
1565 }
1566 }
1567
1568 // If V1Srcs is empty then that means that the phi has no underlying non-phi
1569 // value. This should only be possible in blocks unreachable from the entry
1570 // block, but return MayAlias just in case.
1571 if (V1Srcs.empty())
1572 return MayAlias;
1573
1574 // If this PHI node is recursive, indicate that the pointer may be moved
1575 // across iterations. We can only prove NoAlias if different underlying
1576 // objects are involved.
1577 if (isRecursive)
1578 PNSize = LocationSize::beforeOrAfterPointer();
1579
1580 // In the recursive alias queries below, we may compare values from two
1581 // different loop iterations. Keep track of visited phi blocks, which will
1582 // be used when determining value equivalence.
1583 bool BlockInserted = VisitedPhiBBs.insert(PN->getParent()).second;
1584 auto _ = make_scope_exit([&]() {
1585 if (BlockInserted)
1586 VisitedPhiBBs.erase(PN->getParent());
1587 });
1588
1589 // If we inserted a block into VisitedPhiBBs, alias analysis results that
1590 // have been cached earlier may no longer be valid. Perform recursive queries
1591 // with a new AAQueryInfo.
1592 AAQueryInfo NewAAQI;
1593 AAQueryInfo *UseAAQI = BlockInserted ? &NewAAQI : &AAQI;
1594
1595 AliasResult Alias = aliasCheck(V2, V2Size, V2AAInfo, V1Srcs[0], PNSize,
1596 PNAAInfo, *UseAAQI, UnderV2);
1597
1598 // Early exit if the check of the first PHI source against V2 is MayAlias.
1599 // Other results are not possible.
1600 if (Alias == MayAlias)
1601 return MayAlias;
1602 // With recursive phis we cannot guarantee that MustAlias/PartialAlias will
1603 // remain valid to all elements and needs to conservatively return MayAlias.
1604 if (isRecursive && Alias != NoAlias)
1605 return MayAlias;
1606
1607 // If all sources of the PHI node NoAlias or MustAlias V2, then returns
1608 // NoAlias / MustAlias. Otherwise, returns MayAlias.
1609 for (unsigned i = 1, e = V1Srcs.size(); i != e; ++i) {
1610 Value *V = V1Srcs[i];
1611
1612 AliasResult ThisAlias = aliasCheck(V2, V2Size, V2AAInfo, V, PNSize,
1613 PNAAInfo, *UseAAQI, UnderV2);
1614 Alias = MergeAliasResults(ThisAlias, Alias);
1615 if (Alias == MayAlias)
1616 break;
1617 }
1618
1619 return Alias;
1620}
1621
1622/// Provides a bunch of ad-hoc rules to disambiguate in common cases, such as
1623/// array references.
1624AliasResult BasicAAResult::aliasCheck(const Value *V1, LocationSize V1Size,
1625 const AAMDNodes &V1AAInfo,
1626 const Value *V2, LocationSize V2Size,
1627 const AAMDNodes &V2AAInfo,
1628 AAQueryInfo &AAQI, const Value *O1,
1629 const Value *O2) {
1630 // If either of the memory references is empty, it doesn't matter what the
1631 // pointer values are.
1632 if (V1Size.isZero() || V2Size.isZero())
1633 return NoAlias;
1634
1635 // Strip off any casts if they exist.
1636 V1 = V1->stripPointerCastsAndInvariantGroups();
1637 V2 = V2->stripPointerCastsAndInvariantGroups();
1638
1639 // If V1 or V2 is undef, the result is NoAlias because we can always pick a
1640 // value for undef that aliases nothing in the program.
1641 if (isa<UndefValue>(V1) || isa<UndefValue>(V2))
1642 return NoAlias;
1643
1644 // Are we checking for alias of the same value?
1645 // Because we look 'through' phi nodes, we could look at "Value" pointers from
1646 // different iterations. We must therefore make sure that this is not the
1647 // case. The function isValueEqualInPotentialCycles ensures that this cannot
1648 // happen by looking at the visited phi nodes and making sure they cannot
1649 // reach the value.
1650 if (isValueEqualInPotentialCycles(V1, V2))
1651 return MustAlias;
1652
1653 if (!V1->getType()->isPointerTy() || !V2->getType()->isPointerTy())
1654 return NoAlias; // Scalars cannot alias each other
1655
1656 // Figure out what objects these things are pointing to if we can.
1657 if (O1 == nullptr)
1658 O1 = getUnderlyingObject(V1, MaxLookupSearchDepth);
1659
1660 if (O2 == nullptr)
1661 O2 = getUnderlyingObject(V2, MaxLookupSearchDepth);
1662
1663 // Null values in the default address space don't point to any object, so they
1664 // don't alias any other pointer.
1665 if (const ConstantPointerNull *CPN = dyn_cast<ConstantPointerNull>(O1))
1666 if (!NullPointerIsDefined(&F, CPN->getType()->getAddressSpace()))
1667 return NoAlias;
1668 if (const ConstantPointerNull *CPN = dyn_cast<ConstantPointerNull>(O2))
1669 if (!NullPointerIsDefined(&F, CPN->getType()->getAddressSpace()))
1670 return NoAlias;
1671
1672 if (O1 != O2) {
1673 // If V1/V2 point to two different objects, we know that we have no alias.
1674 if (isIdentifiedObject(O1) && isIdentifiedObject(O2))
1675 return NoAlias;
1676
1677 // Constant pointers can't alias with non-const isIdentifiedObject objects.
1678 if ((isa<Constant>(O1) && isIdentifiedObject(O2) && !isa<Constant>(O2)) ||
1679 (isa<Constant>(O2) && isIdentifiedObject(O1) && !isa<Constant>(O1)))
1680 return NoAlias;
1681
1682 // Function arguments can't alias with things that are known to be
1683 // unambigously identified at the function level.
1684 if ((isa<Argument>(O1) && isIdentifiedFunctionLocal(O2)) ||
1685 (isa<Argument>(O2) && isIdentifiedFunctionLocal(O1)))
1686 return NoAlias;
1687
1688 // If one pointer is the result of a call/invoke or load and the other is a
1689 // non-escaping local object within the same function, then we know the
1690 // object couldn't escape to a point where the call could return it.
1691 //
1692 // Note that if the pointers are in different functions, there are a
1693 // variety of complications. A call with a nocapture argument may still
1694 // temporary store the nocapture argument's value in a temporary memory
1695 // location if that memory location doesn't escape. Or it may pass a
1696 // nocapture value to other functions as long as they don't capture it.
1697 if (isEscapeSource(O1) &&
1698 isNonEscapingLocalObject(O2, &AAQI.IsCapturedCache))
1699 return NoAlias;
1700 if (isEscapeSource(O2) &&
1701 isNonEscapingLocalObject(O1, &AAQI.IsCapturedCache))
1702 return NoAlias;
1703 }
1704
1705 // If the size of one access is larger than the entire object on the other
1706 // side, then we know such behavior is undefined and can assume no alias.
1707 bool NullIsValidLocation = NullPointerIsDefined(&F);
1708 if ((isObjectSmallerThan(
1709 O2, getMinimalExtentFrom(*V1, V1Size, DL, NullIsValidLocation), DL,
1710 TLI, NullIsValidLocation)) ||
1711 (isObjectSmallerThan(
1712 O1, getMinimalExtentFrom(*V2, V2Size, DL, NullIsValidLocation), DL,
1713 TLI, NullIsValidLocation)))
1714 return NoAlias;
1715
1716 // If one the accesses may be before the accessed pointer, canonicalize this
1717 // by using unknown after-pointer sizes for both accesses. This is
1718 // equivalent, because regardless of which pointer is lower, one of them
1719 // will always came after the other, as long as the underlying objects aren't
1720 // disjoint. We do this so that the rest of BasicAA does not have to deal
1721 // with accesses before the base pointer, and to improve cache utilization by
1722 // merging equivalent states.
1723 if (V1Size.mayBeBeforePointer() || V2Size.mayBeBeforePointer()) {
1724 V1Size = LocationSize::afterPointer();
1725 V2Size = LocationSize::afterPointer();
1726 }
1727
1728 // Check the cache before climbing up use-def chains. This also terminates
1729 // otherwise infinitely recursive queries.
1730 AAQueryInfo::LocPair Locs(MemoryLocation(V1, V1Size, V1AAInfo),
1731 MemoryLocation(V2, V2Size, V2AAInfo));
1732 if (V1 > V2)
1733 std::swap(Locs.first, Locs.second);
1734 std::pair<AAQueryInfo::AliasCacheT::iterator, bool> Pair =
1735 AAQI.AliasCache.try_emplace(Locs, MayAlias);
1736 if (!Pair.second)
1737 return Pair.first->second;
1738
1739 if (const GEPOperator *GV1 = dyn_cast<GEPOperator>(V1)) {
1740 AliasResult Result =
1741 aliasGEP(GV1, V1Size, V1AAInfo, V2, V2Size, V2AAInfo, O1, O2, AAQI);
1742 if (Result != MayAlias)
1743 return AAQI.updateResult(Locs, Result);
1744 } else if (const GEPOperator *GV2 = dyn_cast<GEPOperator>(V2)) {
1745 AliasResult Result =
1746 aliasGEP(GV2, V2Size, V2AAInfo, V1, V1Size, V1AAInfo, O2, O1, AAQI);
1747 if (Result != MayAlias)
1748 return AAQI.updateResult(Locs, Result);
1749 }
1750
1751 if (const PHINode *PN = dyn_cast<PHINode>(V1)) {
1752 AliasResult Result =
1753 aliasPHI(PN, V1Size, V1AAInfo, V2, V2Size, V2AAInfo, O2, AAQI);
1754 if (Result != MayAlias)
1755 return AAQI.updateResult(Locs, Result);
1756 } else if (const PHINode *PN = dyn_cast<PHINode>(V2)) {
1757 AliasResult Result =
1758 aliasPHI(PN, V2Size, V2AAInfo, V1, V1Size, V1AAInfo, O1, AAQI);
1759 if (Result != MayAlias)
1760 return AAQI.updateResult(Locs, Result);
1761 }
1762
1763 if (const SelectInst *S1 = dyn_cast<SelectInst>(V1)) {
1764 AliasResult Result =
1765 aliasSelect(S1, V1Size, V1AAInfo, V2, V2Size, V2AAInfo, O2, AAQI);
1766 if (Result != MayAlias)
1767 return AAQI.updateResult(Locs, Result);
1768 } else if (const SelectInst *S2 = dyn_cast<SelectInst>(V2)) {
1769 AliasResult Result =
1770 aliasSelect(S2, V2Size, V2AAInfo, V1, V1Size, V1AAInfo, O1, AAQI);
1771 if (Result != MayAlias)
1772 return AAQI.updateResult(Locs, Result);
1773 }
1774
1775 // If both pointers are pointing into the same object and one of them
1776 // accesses the entire object, then the accesses must overlap in some way.
1777 if (O1 == O2)
1778 if (V1Size.isPrecise() && V2Size.isPrecise() &&
1779 (isObjectSize(O1, V1Size.getValue(), DL, TLI, NullIsValidLocation) ||
1780 isObjectSize(O2, V2Size.getValue(), DL, TLI, NullIsValidLocation)))
1781 return AAQI.updateResult(Locs, PartialAlias);
1782
1783 // Recurse back into the best AA results we have, potentially with refined
1784 // memory locations. We have already ensured that BasicAA has a MayAlias
1785 // cache result for these, so any recursion back into BasicAA won't loop.
1786 AliasResult Result = getBestAAResults().alias(Locs.first, Locs.second, AAQI);
1787 if (Result != MayAlias)
1788 return AAQI.updateResult(Locs, Result);
1789
1790 // MayAlias is already in the cache.
1791 return MayAlias;
1792}
1793
1794/// Check whether two Values can be considered equivalent.
1795///
1796/// In addition to pointer equivalence of \p V1 and \p V2 this checks whether
1797/// they can not be part of a cycle in the value graph by looking at all
1798/// visited phi nodes an making sure that the phis cannot reach the value. We
1799/// have to do this because we are looking through phi nodes (That is we say
1800/// noalias(V, phi(VA, VB)) if noalias(V, VA) and noalias(V, VB).
1801bool BasicAAResult::isValueEqualInPotentialCycles(const Value *V,
1802 const Value *V2) {
1803 if (V != V2)
1804 return false;
1805
1806 const Instruction *Inst = dyn_cast<Instruction>(V);
1807 if (!Inst)
1808 return true;
1809
1810 if (VisitedPhiBBs.empty())
1811 return true;
1812
1813 if (VisitedPhiBBs.size() > MaxNumPhiBBsValueReachabilityCheck)
1814 return false;
1815
1816 // Make sure that the visited phis cannot reach the Value. This ensures that
1817 // the Values cannot come from different iterations of a potential cycle the
1818 // phi nodes could be involved in.
1819 for (auto *P : VisitedPhiBBs)
1820 if (isPotentiallyReachable(&P->front(), Inst, nullptr, DT, LI))
1821 return false;
1822
1823 return true;
1824}
1825
1826/// Computes the symbolic difference between two de-composed GEPs.
1827///
1828/// Dest and Src are the variable indices from two decomposed GetElementPtr
1829/// instructions GEP1 and GEP2 which have common base pointers.
1830void BasicAAResult::GetIndexDifference(
1831 SmallVectorImpl<VariableGEPIndex> &Dest,
1832 const SmallVectorImpl<VariableGEPIndex> &Src) {
1833 if (Src.empty())
1834 return;
1835
1836 for (unsigned i = 0, e = Src.size(); i != e; ++i) {
1837 const Value *V = Src[i].V;
1838 unsigned ZExtBits = Src[i].ZExtBits, SExtBits = Src[i].SExtBits;
1839 APInt Scale = Src[i].Scale;
1840
1841 // Find V in Dest. This is N^2, but pointer indices almost never have more
1842 // than a few variable indexes.
1843 for (unsigned j = 0, e = Dest.size(); j != e; ++j) {
1844 if (!isValueEqualInPotentialCycles(Dest[j].V, V) ||
1845 Dest[j].ZExtBits != ZExtBits || Dest[j].SExtBits != SExtBits)
1846 continue;
1847
1848 // If we found it, subtract off Scale V's from the entry in Dest. If it
1849 // goes to zero, remove the entry.
1850 if (Dest[j].Scale != Scale)
1851 Dest[j].Scale -= Scale;
1852 else
1853 Dest.erase(Dest.begin() + j);
1854 Scale = 0;
1855 break;
1856 }
1857
1858 // If we didn't consume this entry, add it to the end of the Dest list.
1859 if (!!Scale) {
1860 VariableGEPIndex Entry = {V, ZExtBits, SExtBits, -Scale};
1861 Dest.push_back(Entry);
1862 }
1863 }
1864}
1865
1866bool BasicAAResult::constantOffsetHeuristic(
1867 const SmallVectorImpl<VariableGEPIndex> &VarIndices,
1868 LocationSize MaybeV1Size, LocationSize MaybeV2Size, const APInt &BaseOffset,
1869 AssumptionCache *AC, DominatorTree *DT) {
1870 if (VarIndices.size() != 2 || !MaybeV1Size.hasValue() ||
1
Assuming the condition is false
2
Taking false branch
1871 !MaybeV2Size.hasValue())
1872 return false;
1873
1874 const uint64_t V1Size = MaybeV1Size.getValue();
1875 const uint64_t V2Size = MaybeV2Size.getValue();
1876
1877 const VariableGEPIndex &Var0 = VarIndices[0], &Var1 = VarIndices[1];
1878
1879 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
1880 Var0.Scale != -Var1.Scale)
1881 return false;
1882
1883 unsigned Width = Var1.V->getType()->getIntegerBitWidth();
1884
1885 // We'll strip off the Extensions of Var0 and Var1 and do another round
1886 // of GetLinearExpression decomposition. In the example above, if Var0
1887 // is zext(%x + 1) we should get V1 == %x and V1Offset == 1.
1888
1889 APInt V0Scale(Width, 0), V0Offset(Width, 0), V1Scale(Width, 0),
1890 V1Offset(Width, 0);
1891 bool NSW = true, NUW = true;
1892 unsigned V0ZExtBits = 0, V0SExtBits = 0, V1ZExtBits = 0, V1SExtBits = 0;
1893 const Value *V0 = GetLinearExpression(Var0.V, V0Scale, V0Offset, V0ZExtBits,
6
Calling 'BasicAAResult::GetLinearExpression'
1894 V0SExtBits, DL, 0, AC, DT, NSW, NUW);
1895 NSW = true;
1896 NUW = true;
1897 const Value *V1 = GetLinearExpression(Var1.V, V1Scale, V1Offset, V1ZExtBits,
1898 V1SExtBits, DL, 0, AC, DT, NSW, NUW);
1899
1900 if (V0Scale != V1Scale || V0ZExtBits != V1ZExtBits ||
1901 V0SExtBits != V1SExtBits || !isValueEqualInPotentialCycles(V0, V1))
1902 return false;
1903
1904 // We have a hit - Var0 and Var1 only differ by a constant offset!
1905
1906 // If we've been sext'ed then zext'd the maximum difference between Var0 and
1907 // Var1 is possible to calculate, but we're just interested in the absolute
1908 // minimum difference between the two. The minimum distance may occur due to
1909 // wrapping; consider "add i3 %i, 5": if %i == 7 then 7 + 5 mod 8 == 4, and so
1910 // the minimum distance between %i and %i + 5 is 3.
1911 APInt MinDiff = V0Offset - V1Offset, Wrapped = -MinDiff;
1912 MinDiff = APIntOps::umin(MinDiff, Wrapped);
1913 APInt MinDiffBytes =
1914 MinDiff.zextOrTrunc(Var0.Scale.getBitWidth()) * Var0.Scale.abs();
1915
1916 // We can't definitely say whether GEP1 is before or after V2 due to wrapping
1917 // arithmetic (i.e. for some values of GEP1 and V2 GEP1 < V2, and for other
1918 // values GEP1 > V2). We'll therefore only declare NoAlias if both V1Size and
1919 // V2Size can fit in the MinDiffBytes gap.
1920 return MinDiffBytes.uge(V1Size + BaseOffset.abs()) &&
1921 MinDiffBytes.uge(V2Size + BaseOffset.abs());
1922}
1923
1924//===----------------------------------------------------------------------===//
1925// BasicAliasAnalysis Pass
1926//===----------------------------------------------------------------------===//
1927
1928AnalysisKey BasicAA::Key;
1929
1930BasicAAResult BasicAA::run(Function &F, FunctionAnalysisManager &AM) {
1931 return BasicAAResult(F.getParent()->getDataLayout(),
1932 F,
1933 AM.getResult<TargetLibraryAnalysis>(F),
1934 AM.getResult<AssumptionAnalysis>(F),
1935 &AM.getResult<DominatorTreeAnalysis>(F),
1936 AM.getCachedResult<LoopAnalysis>(F),
1937 AM.getCachedResult<PhiValuesAnalysis>(F));
1938}
1939
1940BasicAAWrapperPass::BasicAAWrapperPass() : FunctionPass(ID) {
1941 initializeBasicAAWrapperPassPass(*PassRegistry::getPassRegistry());
1942}
1943
1944char BasicAAWrapperPass::ID = 0;
1945
1946void BasicAAWrapperPass::anchor() {}
1947
1948INITIALIZE_PASS_BEGIN(BasicAAWrapperPass, "basic-aa",static void *initializeBasicAAWrapperPassPassOnce(PassRegistry
&Registry) {
1949 "Basic Alias Analysis (stateless AA impl)", true, true)static void *initializeBasicAAWrapperPassPassOnce(PassRegistry
&Registry) {
1950INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)initializeAssumptionCacheTrackerPass(Registry);
1951INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)initializeDominatorTreeWrapperPassPass(Registry);
1952INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)initializeTargetLibraryInfoWrapperPassPass(Registry);
1953INITIALIZE_PASS_DEPENDENCY(PhiValuesWrapperPass)initializePhiValuesWrapperPassPass(Registry);
1954INITIALIZE_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)); }
1955 "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)); }
1956
1957FunctionPass *llvm::createBasicAAWrapperPass() {
1958 return new BasicAAWrapperPass();
1959}
1960
1961bool BasicAAWrapperPass::runOnFunction(Function &F) {
1962 auto &ACT = getAnalysis<AssumptionCacheTracker>();
1963 auto &TLIWP = getAnalysis<TargetLibraryInfoWrapperPass>();
1964 auto &DTWP = getAnalysis<DominatorTreeWrapperPass>();
1965 auto *LIWP = getAnalysisIfAvailable<LoopInfoWrapperPass>();
1966 auto *PVWP = getAnalysisIfAvailable<PhiValuesWrapperPass>();
1967
1968 Result.reset(new BasicAAResult(F.getParent()->getDataLayout(), F,
1969 TLIWP.getTLI(F), ACT.getAssumptionCache(F),
1970 &DTWP.getDomTree(),
1971 LIWP ? &LIWP->getLoopInfo() : nullptr,
1972 PVWP ? &PVWP->getResult() : nullptr));
1973
1974 return false;
1975}
1976
1977void BasicAAWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
1978 AU.setPreservesAll();
1979 AU.addRequired<AssumptionCacheTracker>();
1980 AU.addRequired<DominatorTreeWrapperPass>();
1981 AU.addRequired<TargetLibraryInfoWrapperPass>();
1982 AU.addUsedIfAvailable<PhiValuesWrapperPass>();
1983}
1984
1985BasicAAResult llvm::createLegacyPMBasicAAResult(Pass &P, Function &F) {
1986 return BasicAAResult(
1987 F.getParent()->getDataLayout(), F,
1988 P.getAnalysis<TargetLibraryInfoWrapperPass>().getTLI(F),
1989 P.getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F));
1990}

/build/llvm-toolchain-snapshot-12~++20201129111111+e987fbdd85d/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~++20201129111111+e987fbdd85d/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~++20201129111111+e987fbdd85d/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~++20201129111111+e987fbdd85d/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~++20201129111111+e987fbdd85d/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~++20201129111111+e987fbdd85d/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~++20201129111111+e987fbdd85d/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~++20201129111111+e987fbdd85d/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~++20201129111111+e987fbdd85d/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~++20201129111111+e987fbdd85d/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~++20201129111111+e987fbdd85d/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~++20201129111111+e987fbdd85d/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~++20201129111111+e987fbdd85d/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~++20201129111111+e987fbdd85d/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~++20201129111111+e987fbdd85d/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~++20201129111111+e987fbdd85d/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~++20201129111111+e987fbdd85d/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~++20201129111111+e987fbdd85d/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 /// Truncate to width
1407 ///
1408 /// Make this APInt have the bit width given by \p width. The value is
1409 /// truncated or left alone to make it that width.
1410 APInt truncOrSelf(unsigned width) const;
1411
1412 /// Sign extend or truncate to width
1413 ///
1414 /// Make this APInt have the bit width given by \p width. The value is sign
1415 /// extended, or left alone to make it that width.
1416 APInt sextOrSelf(unsigned width) const;
1417
1418 /// Zero extend or truncate to width
1419 ///
1420 /// Make this APInt have the bit width given by \p width. The value is zero
1421 /// extended, or left alone to make it that width.
1422 APInt zextOrSelf(unsigned width) const;
1423
1424 /// @}
1425 /// \name Bit Manipulation Operators
1426 /// @{
1427
1428 /// Set every bit to 1.
1429 void setAllBits() {
1430 if (isSingleWord())
1431 U.VAL = WORDTYPE_MAX;
1432 else
1433 // Set all the bits in all the words.
1434 memset(U.pVal, -1, getNumWords() * APINT_WORD_SIZE);
1435 // Clear the unused ones
1436 clearUnusedBits();
1437 }
1438
1439 /// Set a given bit to 1.
1440 ///
1441 /// Set the given bit to 1 whose position is given as "bitPosition".
1442 void setBit(unsigned BitPosition) {
1443 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~++20201129111111+e987fbdd85d/llvm/include/llvm/ADT/APInt.h"
, 1443, __PRETTY_FUNCTION__))
;
1444 WordType Mask = maskBit(BitPosition);
1445 if (isSingleWord())
1446 U.VAL |= Mask;
1447 else
1448 U.pVal[whichWord(BitPosition)] |= Mask;
1449 }
1450
1451 /// Set the sign bit to 1.
1452 void setSignBit() {
1453 setBit(BitWidth - 1);
1454 }
1455
1456 /// Set a given bit to a given value.
1457 void setBitVal(unsigned BitPosition, bool BitValue) {
1458 if (BitValue)
1459 setBit(BitPosition);
1460 else
1461 clearBit(BitPosition);
1462 }
1463
1464 /// Set the bits from loBit (inclusive) to hiBit (exclusive) to 1.
1465 /// This function handles "wrap" case when \p loBit >= \p hiBit, and calls
1466 /// setBits when \p loBit < \p hiBit.
1467 /// For \p loBit == \p hiBit wrap case, set every bit to 1.
1468 void setBitsWithWrap(unsigned loBit, unsigned hiBit) {
1469 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~++20201129111111+e987fbdd85d/llvm/include/llvm/ADT/APInt.h"
, 1469, __PRETTY_FUNCTION__))
;
1470 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~++20201129111111+e987fbdd85d/llvm/include/llvm/ADT/APInt.h"
, 1470, __PRETTY_FUNCTION__))
;
1471 if (loBit < hiBit) {
1472 setBits(loBit, hiBit);
1473 return;
1474 }
1475 setLowBits(hiBit);
1476 setHighBits(BitWidth - loBit);
1477 }
1478
1479 /// Set the bits from loBit (inclusive) to hiBit (exclusive) to 1.
1480 /// This function handles case when \p loBit <= \p hiBit.
1481 void setBits(unsigned loBit, unsigned hiBit) {
1482 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~++20201129111111+e987fbdd85d/llvm/include/llvm/ADT/APInt.h"
, 1482, __PRETTY_FUNCTION__))
;
1483 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~++20201129111111+e987fbdd85d/llvm/include/llvm/ADT/APInt.h"
, 1483, __PRETTY_FUNCTION__))
;
1484 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~++20201129111111+e987fbdd85d/llvm/include/llvm/ADT/APInt.h"
, 1484, __PRETTY_FUNCTION__))
;
1485 if (loBit == hiBit)
1486 return;
1487 if (loBit < APINT_BITS_PER_WORD && hiBit <= APINT_BITS_PER_WORD) {
1488 uint64_t mask = WORDTYPE_MAX >> (APINT_BITS_PER_WORD - (hiBit - loBit));
1489 mask <<= loBit;
1490 if (isSingleWord())
1491 U.VAL |= mask;
1492 else
1493 U.pVal[0] |= mask;
1494 } else {
1495 setBitsSlowCase(loBit, hiBit);
1496 }
1497 }
1498
1499 /// Set the top bits starting from loBit.
1500 void setBitsFrom(unsigned loBit) {
1501 return setBits(loBit, BitWidth);
1502 }
1503
1504 /// Set the bottom loBits bits.
1505 void setLowBits(unsigned loBits) {
1506 return setBits(0, loBits);
1507 }
1508
1509 /// Set the top hiBits bits.
1510 void setHighBits(unsigned hiBits) {
1511 return setBits(BitWidth - hiBits, BitWidth);
1512 }
1513
1514 /// Set every bit to 0.
1515 void clearAllBits() {
1516 if (isSingleWord())
1517 U.VAL = 0;
1518 else
1519 memset(U.pVal, 0, getNumWords() * APINT_WORD_SIZE);
1520 }
1521
1522 /// Set a given bit to 0.
1523 ///
1524 /// Set the given bit to 0 whose position is given as "bitPosition".
1525 void clearBit(unsigned BitPosition) {
1526 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~++20201129111111+e987fbdd85d/llvm/include/llvm/ADT/APInt.h"
, 1526, __PRETTY_FUNCTION__))
;
1527 WordType Mask = ~maskBit(BitPosition);
1528 if (isSingleWord())
1529 U.VAL &= Mask;
1530 else
1531 U.pVal[whichWord(BitPosition)] &= Mask;
1532 }
1533
1534 /// Set bottom loBits bits to 0.
1535 void clearLowBits(unsigned loBits) {
1536 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~++20201129111111+e987fbdd85d/llvm/include/llvm/ADT/APInt.h"
, 1536, __PRETTY_FUNCTION__))
;
1537 APInt Keep = getHighBitsSet(BitWidth, BitWidth - loBits);
1538 *this &= Keep;
1539 }
1540
1541 /// Set the sign bit to 0.
1542 void clearSignBit() {
1543 clearBit(BitWidth - 1);
1544 }
1545
1546 /// Toggle every bit to its opposite value.
1547 void flipAllBits() {
1548 if (isSingleWord()) {
1549 U.VAL ^= WORDTYPE_MAX;
1550 clearUnusedBits();
1551 } else {
1552 flipAllBitsSlowCase();
1553 }
1554 }
1555
1556 /// Toggles a given bit to its opposite value.
1557 ///
1558 /// Toggle a given bit to its opposite value whose position is given
1559 /// as "bitPosition".
1560 void flipBit(unsigned bitPosition);
1561
1562 /// Negate this APInt in place.
1563 void negate() {
1564 flipAllBits();
1565 ++(*this);
1566 }
1567
1568 /// Insert the bits from a smaller APInt starting at bitPosition.
1569 void insertBits(const APInt &SubBits, unsigned bitPosition);
1570 void insertBits(uint64_t SubBits, unsigned bitPosition, unsigned numBits);
1571
1572 /// Return an APInt with the extracted bits [bitPosition,bitPosition+numBits).
1573 APInt extractBits(unsigned numBits, unsigned bitPosition) const;
1574 uint64_t extractBitsAsZExtValue(unsigned numBits, unsigned bitPosition) const;
1575
1576 /// @}
1577 /// \name Value Characterization Functions
1578 /// @{
1579
1580 /// Return the number of bits in the APInt.
1581 unsigned getBitWidth() const { return BitWidth; }
1582
1583 /// Get the number of words.
1584 ///
1585 /// Here one word's bitwidth equals to that of uint64_t.
1586 ///
1587 /// \returns the number of words to hold the integer value of this APInt.
1588 unsigned getNumWords() const { return getNumWords(BitWidth); }
1589
1590 /// Get the number of words.
1591 ///
1592 /// *NOTE* Here one word's bitwidth equals to that of uint64_t.
1593 ///
1594 /// \returns the number of words to hold the integer value with a given bit
1595 /// width.
1596 static unsigned getNumWords(unsigned BitWidth) {
1597 return ((uint64_t)BitWidth + APINT_BITS_PER_WORD - 1) / APINT_BITS_PER_WORD;
1598 }
1599
1600 /// Compute the number of active bits in the value
1601 ///
1602 /// This function returns the number of active bits which is defined as the
1603 /// bit width minus the number of leading zeros. This is used in several
1604 /// computations to see how "wide" the value is.
1605 unsigned getActiveBits() const { return BitWidth - countLeadingZeros(); }
1606
1607 /// Compute the number of active words in the value of this APInt.
1608 ///
1609 /// This is used in conjunction with getActiveData to extract the raw value of
1610 /// the APInt.
1611 unsigned getActiveWords() const {
1612 unsigned numActiveBits = getActiveBits();
1613 return numActiveBits ? whichWord(numActiveBits - 1) + 1 : 1;
1614 }
1615
1616 /// Get the minimum bit size for this signed APInt
1617 ///
1618 /// Computes the minimum bit width for this APInt while considering it to be a
1619 /// signed (and probably negative) value. If the value is not negative, this
1620 /// function returns the same value as getActiveBits()+1. Otherwise, it
1621 /// returns the smallest bit width that will retain the negative value. For
1622 /// example, -1 can be written as 0b1 or 0xFFFFFFFFFF. 0b1 is shorter and so
1623 /// for -1, this function will always return 1.
1624 unsigned getMinSignedBits() const { return BitWidth - getNumSignBits() + 1; }
1625
1626 /// Get zero extended value
1627 ///
1628 /// This method attempts to return the value of this APInt as a zero extended
1629 /// uint64_t. The bitwidth must be <= 64 or the value must fit within a
1630 /// uint64_t. Otherwise an assertion will result.
1631 uint64_t getZExtValue() const {
1632 if (isSingleWord())
1633 return U.VAL;
1634 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~++20201129111111+e987fbdd85d/llvm/include/llvm/ADT/APInt.h"
, 1634, __PRETTY_FUNCTION__))
;
1635 return U.pVal[0];
1636 }
1637
1638 /// Get sign extended value
1639 ///
1640 /// This method attempts to return the value of this APInt as a sign extended
1641 /// int64_t. The bit width must be <= 64 or the value must fit within an
1642 /// int64_t. Otherwise an assertion will result.
1643 int64_t getSExtValue() const {
1644 if (isSingleWord())
1645 return SignExtend64(U.VAL, BitWidth);
1646 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~++20201129111111+e987fbdd85d/llvm/include/llvm/ADT/APInt.h"
, 1646, __PRETTY_FUNCTION__))
;
1647 return int64_t(U.pVal[0]);
1648 }
1649
1650 /// Get bits required for string value.
1651 ///
1652 /// This method determines how many bits are required to hold the APInt
1653 /// equivalent of the string given by \p str.
1654 static unsigned getBitsNeeded(StringRef str, uint8_t radix);
1655
1656 /// The APInt version of the countLeadingZeros functions in
1657 /// MathExtras.h.
1658 ///
1659 /// It counts the number of zeros from the most significant bit to the first
1660 /// one bit.
1661 ///
1662 /// \returns BitWidth if the value is zero, otherwise returns the number of
1663 /// zeros from the most significant bit to the first one bits.
1664 unsigned countLeadingZeros() const {
1665 if (isSingleWord()) {
1666 unsigned unusedBits = APINT_BITS_PER_WORD - BitWidth;
1667 return llvm::countLeadingZeros(U.VAL) - unusedBits;
1668 }
1669 return countLeadingZerosSlowCase();
1670 }
1671
1672 /// Count the number of leading one bits.
1673 ///
1674 /// This function is an APInt version of the countLeadingOnes
1675 /// functions in MathExtras.h. It counts the number of ones from the most
1676 /// significant bit to the first zero bit.
1677 ///
1678 /// \returns 0 if the high order bit is not set, otherwise returns the number
1679 /// of 1 bits from the most significant to the least
1680 unsigned countLeadingOnes() const {
1681 if (isSingleWord())
1682 return llvm::countLeadingOnes(U.VAL << (APINT_BITS_PER_WORD - BitWidth));
1683 return countLeadingOnesSlowCase();
1684 }
1685
1686 /// Computes the number of leading bits of this APInt that are equal to its
1687 /// sign bit.
1688 unsigned getNumSignBits() const {
1689 return isNegative() ? countLeadingOnes() : countLeadingZeros();
1690 }
1691
1692 /// Count the number of trailing zero bits.
1693 ///
1694 /// This function is an APInt version of the countTrailingZeros
1695 /// functions in MathExtras.h. It counts the number of zeros from the least
1696 /// significant bit to the first set bit.
1697 ///
1698 /// \returns BitWidth if the value is zero, otherwise returns the number of
1699 /// zeros from the least significant bit to the first one bit.
1700 unsigned countTrailingZeros() const {
1701 if (isSingleWord())
1702 return std::min(unsigned(llvm::countTrailingZeros(U.VAL)), BitWidth);
1703 return countTrailingZerosSlowCase();
1704 }
1705
1706 /// Count the number of trailing one bits.
1707 ///
1708 /// This function is an APInt version of the countTrailingOnes
1709 /// functions in MathExtras.h. It counts the number of ones from the least
1710 /// significant bit to the first zero bit.
1711 ///
1712 /// \returns BitWidth if the value is all ones, otherwise returns the number
1713 /// of ones from the least significant bit to the first zero bit.
1714 unsigned countTrailingOnes() const {
1715 if (isSingleWord())
1716 return llvm::countTrailingOnes(U.VAL);
1717 return countTrailingOnesSlowCase();
1718 }
1719
1720 /// Count the number of bits set.
1721 ///
1722 /// This function is an APInt version of the countPopulation functions
1723 /// in MathExtras.h. It counts the number of 1 bits in the APInt value.
1724 ///
1725 /// \returns 0 if the value is zero, otherwise returns the number of set bits.
1726 unsigned countPopulation() const {
1727 if (isSingleWord())
1728 return llvm::countPopulation(U.VAL);
1729 return countPopulationSlowCase();
1730 }
1731
1732 /// @}
1733 /// \name Conversion Functions
1734 /// @{
1735 void print(raw_ostream &OS, bool isSigned) const;
1736
1737 /// Converts an APInt to a string and append it to Str. Str is commonly a
1738 /// SmallString.
1739 void toString(SmallVectorImpl<char> &Str, unsigned Radix, bool Signed,
1740 bool formatAsCLiteral = false) const;
1741
1742 /// Considers the APInt to be unsigned and converts it into a string in the
1743 /// radix given. The radix can be 2, 8, 10 16, or 36.
1744 void toStringUnsigned(SmallVectorImpl<char> &Str, unsigned Radix = 10) const {
1745 toString(Str, Radix, false, false);
1746 }
1747
1748 /// Considers the APInt to be signed and converts it into a string in the
1749 /// radix given. The radix can be 2, 8, 10, 16, or 36.
1750 void toStringSigned(SmallVectorImpl<char> &Str, unsigned Radix = 10) const {
1751 toString(Str, Radix, true, false);
1752 }
1753
1754 /// Return the APInt as a std::string.
1755 ///
1756 /// Note that this is an inefficient method. It is better to pass in a
1757 /// SmallVector/SmallString to the methods above to avoid thrashing the heap
1758 /// for the string.
1759 std::string toString(unsigned Radix, bool Signed) const;
1760
1761 /// \returns a byte-swapped representation of this APInt Value.
1762 APInt byteSwap() const;
1763
1764 /// \returns the value with the bit representation reversed of this APInt
1765 /// Value.
1766 APInt reverseBits() const;
1767
1768 /// Converts this APInt to a double value.
1769 double roundToDouble(bool isSigned) const;
1770
1771 /// Converts this unsigned APInt to a double value.
1772 double roundToDouble() const { return roundToDouble(false); }
1773
1774 /// Converts this signed APInt to a double value.
1775 double signedRoundToDouble() const { return roundToDouble(true); }
1776
1777 /// Converts APInt bits to a double
1778 ///
1779 /// The conversion does not do a translation from integer to double, it just
1780 /// re-interprets the bits as a double. Note that it is valid to do this on
1781 /// any bit width. Exactly 64 bits will be translated.
1782 double bitsToDouble() const {
1783 return BitsToDouble(getWord(0));
1784 }
1785
1786 /// Converts APInt bits to a float
1787 ///
1788 /// The conversion does not do a translation from integer to float, it just
1789 /// re-interprets the bits as a float. Note that it is valid to do this on
1790 /// any bit width. Exactly 32 bits will be translated.
1791 float bitsToFloat() const {
1792 return BitsToFloat(static_cast<uint32_t>(getWord(0)));
1793 }
1794
1795 /// Converts a double to APInt bits.
1796 ///
1797 /// The conversion does not do a translation from double to integer, it just
1798 /// re-interprets the bits of the double.
1799 static APInt doubleToBits(double V) {
1800 return APInt(sizeof(double) * CHAR_BIT8, DoubleToBits(V));
1801 }
1802
1803 /// Converts a float to APInt bits.
1804 ///
1805 /// The conversion does not do a translation from float to integer, it just
1806 /// re-interprets the bits of the float.
1807 static APInt floatToBits(float V) {
1808 return APInt(sizeof(float) * CHAR_BIT8, FloatToBits(V));
1809 }
1810
1811 /// @}
1812 /// \name Mathematics Operations
1813 /// @{
1814
1815 /// \returns the floor log base 2 of this APInt.
1816 unsigned logBase2() const { return getActiveBits() - 1; }
1817
1818 /// \returns the ceil log base 2 of this APInt.
1819 unsigned ceilLogBase2() const {
1820 APInt temp(*this);
1821 --temp;
1822 return temp.getActiveBits();
1823 }
1824
1825 /// \returns the nearest log base 2 of this APInt. Ties round up.
1826 ///
1827 /// NOTE: When we have a BitWidth of 1, we define:
1828 ///
1829 /// log2(0) = UINT32_MAX
1830 /// log2(1) = 0
1831 ///
1832 /// to get around any mathematical concerns resulting from
1833 /// referencing 2 in a space where 2 does no exist.
1834 unsigned nearestLogBase2() const {
1835 // Special case when we have a bitwidth of 1. If VAL is 1, then we
1836 // get 0. If VAL is 0, we get WORDTYPE_MAX which gets truncated to
1837 // UINT32_MAX.
1838 if (BitWidth == 1)
1839 return U.VAL - 1;
1840
1841 // Handle the zero case.
1842 if (isNullValue())
1843 return UINT32_MAX(4294967295U);
1844
1845 // The non-zero case is handled by computing:
1846 //
1847 // nearestLogBase2(x) = logBase2(x) + x[logBase2(x)-1].
1848 //
1849 // where x[i] is referring to the value of the ith bit of x.
1850 unsigned lg = logBase2();
1851 return lg + unsigned((*this)[lg - 1]);
1852 }
1853
1854 /// \returns the log base 2 of this APInt if its an exact power of two, -1
1855 /// otherwise
1856 int32_t exactLogBase2() const {
1857 if (!isPowerOf2())
1858 return -1;
1859 return logBase2();
1860 }
1861
1862 /// Compute the square root
1863 APInt sqrt() const;
1864
1865 /// Get the absolute value;
1866 ///
1867 /// If *this is < 0 then return -(*this), otherwise *this;
1868 APInt abs() const {
1869 if (isNegative())
1870 return -(*this);
1871 return *this;
1872 }
1873
1874 /// \returns the multiplicative inverse for a given modulo.
1875 APInt multiplicativeInverse(const APInt &modulo) const;
1876
1877 /// @}
1878 /// \name Support for division by constant
1879 /// @{
1880
1881 /// Calculate the magic number for signed division by a constant.
1882 struct ms;
1883 ms magic() const;
1884
1885 /// Calculate the magic number for unsigned division by a constant.
1886 struct mu;
1887 mu magicu(unsigned LeadingZeros = 0) const;
1888
1889 /// @}
1890 /// \name Building-block Operations for APInt and APFloat
1891 /// @{
1892
1893 // These building block operations operate on a representation of arbitrary
1894 // precision, two's-complement, bignum integer values. They should be
1895 // sufficient to implement APInt and APFloat bignum requirements. Inputs are
1896 // generally a pointer to the base of an array of integer parts, representing
1897 // an unsigned bignum, and a count of how many parts there are.
1898
1899 /// Sets the least significant part of a bignum to the input value, and zeroes
1900 /// out higher parts.
1901 static void tcSet(WordType *, WordType, unsigned);
1902
1903 /// Assign one bignum to another.
1904 static void tcAssign(WordType *, const WordType *, unsigned);
1905
1906 /// Returns true if a bignum is zero, false otherwise.
1907 static bool tcIsZero(const WordType *, unsigned);
1908
1909 /// Extract the given bit of a bignum; returns 0 or 1. Zero-based.
1910 static int tcExtractBit(const WordType *, unsigned bit);
1911
1912 /// Copy the bit vector of width srcBITS from SRC, starting at bit srcLSB, to
1913 /// DST, of dstCOUNT parts, such that the bit srcLSB becomes the least
1914 /// significant bit of DST. All high bits above srcBITS in DST are
1915 /// zero-filled.
1916 static void tcExtract(WordType *, unsigned dstCount,
1917 const WordType *, unsigned srcBits,
1918 unsigned srcLSB);
1919
1920 /// Set the given bit of a bignum. Zero-based.
1921 static void tcSetBit(WordType *, unsigned bit);
1922
1923 /// Clear the given bit of a bignum. Zero-based.
1924 static void tcClearBit(WordType *, unsigned bit);
1925
1926 /// Returns the bit number of the least or most significant set bit of a
1927 /// number. If the input number has no bits set -1U is returned.
1928 static unsigned tcLSB(const WordType *, unsigned n);
1929 static unsigned tcMSB(const WordType *parts, unsigned n);
1930
1931 /// Negate a bignum in-place.
1932 static void tcNegate(WordType *, unsigned);
1933
1934 /// DST += RHS + CARRY where CARRY is zero or one. Returns the carry flag.
1935 static WordType tcAdd(WordType *, const WordType *,
1936 WordType carry, unsigned);
1937 /// DST += RHS. Returns the carry flag.
1938 static WordType tcAddPart(WordType *, WordType, unsigned);
1939
1940 /// DST -= RHS + CARRY where CARRY is zero or one. Returns the carry flag.
1941 static WordType tcSubtract(WordType *, const WordType *,
1942 WordType carry, unsigned);
1943 /// DST -= RHS. Returns the carry flag.
1944 static WordType tcSubtractPart(WordType *, WordType, unsigned);
1945
1946 /// DST += SRC * MULTIPLIER + PART if add is true
1947 /// DST = SRC * MULTIPLIER + PART if add is false
1948 ///
1949 /// Requires 0 <= DSTPARTS <= SRCPARTS + 1. If DST overlaps SRC they must
1950 /// start at the same point, i.e. DST == SRC.
1951 ///
1952 /// If DSTPARTS == SRC_PARTS + 1 no overflow occurs and zero is returned.
1953 /// Otherwise DST is filled with the least significant DSTPARTS parts of the
1954 /// result, and if all of the omitted higher parts were zero return zero,
1955 /// otherwise overflow occurred and return one.
1956 static int tcMultiplyPart(WordType *dst, const WordType *src,
1957 WordType multiplier, WordType carry,
1958 unsigned srcParts, unsigned dstParts,
1959 bool add);
1960
1961 /// DST = LHS * RHS, where DST has the same width as the operands and is
1962 /// filled with the least significant parts of the result. Returns one if
1963 /// overflow occurred, otherwise zero. DST must be disjoint from both
1964 /// operands.
1965 static int tcMultiply(WordType *, const WordType *, const WordType *,
1966 unsigned);
1967
1968 /// DST = LHS * RHS, where DST has width the sum of the widths of the
1969 /// operands. No overflow occurs. DST must be disjoint from both operands.
1970 static void tcFullMultiply(WordType *, const WordType *,
1971 const WordType *, unsigned, unsigned);
1972
1973 /// If RHS is zero LHS and REMAINDER are left unchanged, return one.
1974 /// Otherwise set LHS to LHS / RHS with the fractional part discarded, set
1975 /// REMAINDER to the remainder, return zero. i.e.
1976 ///
1977 /// OLD_LHS = RHS * LHS + REMAINDER
1978 ///
1979 /// SCRATCH is a bignum of the same size as the operands and result for use by
1980 /// the routine; its contents need not be initialized and are destroyed. LHS,
1981 /// REMAINDER and SCRATCH must be distinct.
1982 static int tcDivide(WordType *lhs, const WordType *rhs,
1983 WordType *remainder, WordType *scratch,
1984 unsigned parts);
1985
1986 /// Shift a bignum left Count bits. Shifted in bits are zero. There are no
1987 /// restrictions on Count.
1988 static void tcShiftLeft(WordType *, unsigned Words, unsigned Count);
1989
1990 /// Shift a bignum right Count bits. Shifted in bits are zero. There are no
1991 /// restrictions on Count.
1992 static void tcShiftRight(WordType *, unsigned Words, unsigned Count);
1993
1994 /// The obvious AND, OR and XOR and complement operations.
1995 static void tcAnd(WordType *, const WordType *, unsigned);
1996 static void tcOr(WordType *, const WordType *, unsigned);
1997 static void tcXor(WordType *, const WordType *, unsigned);
1998 static void tcComplement(WordType *, unsigned);
1999
2000 /// Comparison (unsigned) of two bignums.
2001 static int tcCompare(const WordType *, const WordType *, unsigned);
2002
2003 /// Increment a bignum in-place. Return the carry flag.
2004 static WordType tcIncrement(WordType *dst, unsigned parts) {
2005 return tcAddPart(dst, 1, parts);
2006 }
2007
2008 /// Decrement a bignum in-place. Return the borrow flag.
2009 static WordType tcDecrement(WordType *dst, unsigned parts) {
2010 return tcSubtractPart(dst, 1, parts);
2011 }
2012
2013 /// Set the least significant BITS and clear the rest.
2014 static void tcSetLeastSignificantBits(WordType *, unsigned, unsigned bits);
2015
2016 /// debug method
2017 void dump() const;
2018
2019 /// @}
2020};
2021
2022/// Magic data for optimising signed division by a constant.
2023struct APInt::ms {
2024 APInt m; ///< magic number
2025 unsigned s; ///< shift amount
2026};
2027
2028/// Magic data for optimising unsigned division by a constant.
2029struct APInt::mu {
2030 APInt m; ///< magic number
2031 bool a; ///< add indicator
2032 unsigned s; ///< shift amount
2033};
2034
2035inline bool operator==(uint64_t V1, const APInt &V2) { return V2 == V1; }
2036
2037inline bool operator!=(uint64_t V1, const APInt &V2) { return V2 != V1; }
2038
2039/// Unary bitwise complement operator.
2040///
2041/// \returns an APInt that is the bitwise complement of \p v.
2042inline APInt operator~(APInt v) {
2043 v.flipAllBits();
2044 return v;
2045}
2046
2047inline APInt operator&(APInt a, const APInt &b) {
2048 a &= b;
2049 return a;
2050}
2051
2052inline APInt operator&(const APInt &a, APInt &&b) {
2053 b &= a;
2054 return std::move(b);
2055}
2056
2057inline APInt operator&(APInt a, uint64_t RHS) {
2058 a &= RHS;
2059 return a;
2060}
2061
2062inline APInt operator&(uint64_t LHS, APInt b) {
2063 b &= LHS;
2064 return b;
2065}
2066
2067inline APInt operator|(APInt a, const APInt &b) {
2068 a |= b;
2069 return a;
2070}
2071
2072inline APInt operator|(const APInt &a, APInt &&b) {
2073 b |= a;
2074 return std::move(b);
2075}
2076
2077inline APInt operator|(APInt a, uint64_t RHS) {
2078 a |= RHS;
2079 return a;
2080}
2081
2082inline APInt operator|(uint64_t LHS, APInt b) {
2083 b |= LHS;
2084 return b;
2085}
2086
2087inline APInt operator^(APInt a, const APInt &b) {
2088 a ^= b;
2089 return a;
2090}
2091
2092inline APInt operator^(const APInt &a, APInt &&b) {
2093 b ^= a;
2094 return std::move(b);
2095}
2096
2097inline APInt operator^(APInt a, uint64_t RHS) {
2098 a ^= RHS;
2099 return a;
2100}
2101
2102inline APInt operator^(uint64_t LHS, APInt b) {
2103 b ^= LHS;
2104 return b;
2105}
2106
2107inline raw_ostream &operator<<(raw_ostream &OS, const APInt &I) {
2108 I.print(OS, true);
2109 return OS;
2110}
2111
2112inline APInt operator-(APInt v) {
2113 v.negate();
2114 return v;
2115}
2116
2117inline APInt operator+(APInt a, const APInt &b) {
2118 a += b;
2119 return a;
2120}
2121
2122inline APInt operator+(const APInt &a, APInt &&b) {
2123 b += a;
2124 return std::move(b);
2125}
2126
2127inline APInt operator+(APInt a, uint64_t RHS) {
2128 a += RHS;
2129 return a;
2130}
2131
2132inline APInt operator+(uint64_t LHS, APInt b) {
2133 b += LHS;
2134 return b;
2135}
2136
2137inline APInt operator-(APInt a, const APInt &b) {
2138 a -= b;
2139 return a;
2140}
2141
2142inline APInt operator-(const APInt &a, APInt &&b) {
2143 b.negate();
2144 b += a;
2145 return std::move(b);
2146}
2147
2148inline APInt operator-(APInt a, uint64_t RHS) {
2149 a -= RHS;
2150 return a;
2151}
2152
2153inline APInt operator-(uint64_t LHS, APInt b) {
2154 b.negate();
2155 b += LHS;
2156 return b;
2157}
2158
2159inline APInt operator*(APInt a, uint64_t RHS) {
2160 a *= RHS;
2161 return a;
2162}
2163
2164inline APInt operator*(uint64_t LHS, APInt b) {
2165 b *= LHS;
2166 return b;
2167}
2168
2169
2170namespace APIntOps {
2171
2172/// Determine the smaller of two APInts considered to be signed.
2173inline const APInt &smin(const APInt &A, const APInt &B) {
2174 return A.slt(B) ? A : B;
2175}
2176
2177/// Determine the larger of two APInts considered to be signed.
2178inline const APInt &smax(const APInt &A, const APInt &B) {
2179 return A.sgt(B) ? A : B;
2180}
2181
2182/// Determine the smaller of two APInts considered to be signed.
2183inline const APInt &umin(const APInt &A, const APInt &B) {
2184 return A.ult(B) ? A : B;
2185}
2186
2187/// Determine the larger of two APInts considered to be unsigned.
2188inline const APInt &umax(const APInt &A, const APInt &B) {
2189 return A.ugt(B) ? A : B;
2190}
2191
2192/// Compute GCD of two unsigned APInt values.
2193///
2194/// This function returns the greatest common divisor of the two APInt values
2195/// using Stein's algorithm.
2196///
2197/// \returns the greatest common divisor of A and B.
2198APInt GreatestCommonDivisor(APInt A, APInt B);
2199
2200/// Converts the given APInt to a double value.
2201///
2202/// Treats the APInt as an unsigned value for conversion purposes.
2203inline double RoundAPIntToDouble(const APInt &APIVal) {
2204 return APIVal.roundToDouble();
2205}
2206
2207/// Converts the given APInt to a double value.
2208///
2209/// Treats the APInt as a signed value for conversion purposes.
2210inline double RoundSignedAPIntToDouble(const APInt &APIVal) {
2211 return APIVal.signedRoundToDouble();
2212}
2213
2214/// Converts the given APInt to a float vlalue.
2215inline float RoundAPIntToFloat(const APInt &APIVal) {
2216 return float(RoundAPIntToDouble(APIVal));
2217}
2218
2219/// Converts the given APInt to a float value.
2220///
2221/// Treats the APInt as a signed value for conversion purposes.
2222inline float RoundSignedAPIntToFloat(const APInt &APIVal) {
2223 return float(APIVal.signedRoundToDouble());
2224}
2225
2226/// Converts the given double value into a APInt.
2227///
2228/// This function convert a double value to an APInt value.
2229APInt RoundDoubleToAPInt(double Double, unsigned width);
2230
2231/// Converts a float value into a APInt.
2232///
2233/// Converts a float value into an APInt value.
2234inline APInt RoundFloatToAPInt(float Float, unsigned width) {
2235 return RoundDoubleToAPInt(double(Float), width);
2236}
2237
2238/// Return A unsign-divided by B, rounded by the given rounding mode.
2239APInt RoundingUDiv(const APInt &A, const APInt &B, APInt::Rounding RM);
2240
2241/// Return A sign-divided by B, rounded by the given rounding mode.
2242APInt RoundingSDiv(const APInt &A, const APInt &B, APInt::Rounding RM);
2243
2244/// Let q(n) = An^2 + Bn + C, and BW = bit width of the value range
2245/// (e.g. 32 for i32).
2246/// This function finds the smallest number n, such that
2247/// (a) n >= 0 and q(n) = 0, or
2248/// (b) n >= 1 and q(n-1) and q(n), when evaluated in the set of all
2249/// integers, belong to two different intervals [Rk, Rk+R),
2250/// where R = 2^BW, and k is an integer.
2251/// The idea here is to find when q(n) "overflows" 2^BW, while at the
2252/// same time "allowing" subtraction. In unsigned modulo arithmetic a
2253/// subtraction (treated as addition of negated numbers) would always
2254/// count as an overflow, but here we want to allow values to decrease
2255/// and increase as long as they are within the same interval.
2256/// Specifically, adding of two negative numbers should not cause an
2257/// overflow (as long as the magnitude does not exceed the bit width).
2258/// On the other hand, given a positive number, adding a negative
2259/// number to it can give a negative result, which would cause the
2260/// value to go from [-2^BW, 0) to [0, 2^BW). In that sense, zero is
2261/// treated as a special case of an overflow.
2262///
2263/// This function returns None if after finding k that minimizes the
2264/// positive solution to q(n) = kR, both solutions are contained between
2265/// two consecutive integers.
2266///
2267/// There are cases where q(n) > T, and q(n+1) < T (assuming evaluation
2268/// in arithmetic modulo 2^BW, and treating the values as signed) by the
2269/// virtue of *signed* overflow. This function will *not* find such an n,
2270/// however it may find a value of n satisfying the inequalities due to
2271/// an *unsigned* overflow (if the values are treated as unsigned).
2272/// To find a solution for a signed overflow, treat it as a problem of
2273/// finding an unsigned overflow with a range with of BW-1.
2274///
2275/// The returned value may have a different bit width from the input
2276/// coefficients.
2277Optional<APInt> SolveQuadraticEquationWrap(APInt A, APInt B, APInt C,
2278 unsigned RangeWidth);
2279
2280/// Compare two values, and if they are different, return the position of the
2281/// most significant bit that is different in the values.
2282Optional<unsigned> GetMostSignificantDifferentBit(const APInt &A,
2283 const APInt &B);
2284
2285} // End of APIntOps namespace
2286
2287// See friend declaration above. This additional declaration is required in
2288// order to compile LLVM with IBM xlC compiler.
2289hash_code hash_value(const APInt &Arg);
2290
2291/// StoreIntToMemory - Fills the StoreBytes bytes of memory starting from Dst
2292/// with the integer held in IntVal.
2293void StoreIntToMemory(const APInt &IntVal, uint8_t *Dst, unsigned StoreBytes);
2294
2295/// LoadIntFromMemory - Loads the integer stored in the LoadBytes bytes starting
2296/// from Src into IntVal, which is assumed to be wide enough and to hold zero.
2297void LoadIntFromMemory(APInt &IntVal, const uint8_t *Src, unsigned LoadBytes);
2298
2299} // namespace llvm
2300
2301#endif