LLVM 19.0.0git
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1//===- llvm/Transforms/Utils/UnrollLoop.h - Unrolling utilities -*- C++ -*-===//
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
9// This file defines some loop unrolling utilities. It does not define any
10// actual pass or policy, but provides a single function to perform loop
11// unrolling.
18#include "llvm/ADT/DenseMap.h"
22namespace llvm {
24class AssumptionCache;
25class AAResults;
26class BasicBlock;
27class BlockFrequencyInfo;
28class DependenceInfo;
29class DominatorTree;
30class Loop;
31class LoopInfo;
32class MDNode;
33class ProfileSummaryInfo;
34class OptimizationRemarkEmitter;
35class ScalarEvolution;
36class StringRef;
37class Value;
41/// @{
42/// Metadata attribute names
43const char *const LLVMLoopUnrollFollowupAll = "llvm.loop.unroll.followup_all";
45 "llvm.loop.unroll.followup_unrolled";
47 "llvm.loop.unroll.followup_remainder";
48/// @}
51 BasicBlock *ClonedBB, LoopInfo *LI,
52 NewLoopsMap &NewLoops);
54/// Represents the result of a \c UnrollLoop invocation.
55enum class LoopUnrollResult {
56 /// The loop was not modified.
59 /// The loop was partially unrolled -- we still have a loop, but with a
60 /// smaller trip count. We may also have emitted epilogue loop if the loop
61 /// had a non-constant trip count.
64 /// The loop was fully unrolled into straight-line code. We no longer have
65 /// any back-edges.
70 unsigned Count;
71 bool Force;
72 bool Runtime;
82 OptimizationRemarkEmitter *ORE, bool PreserveLCSSA,
83 Loop **RemainderLoop = nullptr,
84 AAResults *AA = nullptr);
87 Loop *L, unsigned Count, bool AllowExpensiveTripCount,
88 bool UseEpilogRemainder, bool UnrollRemainder, bool ForgetAllSCEV,
90 const TargetTransformInfo *TTI, bool PreserveLCSSA,
91 Loop **ResultLoop = nullptr);
93LoopUnrollResult UnrollAndJamLoop(Loop *L, unsigned Count, unsigned TripCount,
94 unsigned TripMultiple, bool UnrollRemainder,
99 Loop **EpilogueLoop = nullptr);
102 DependenceInfo &DI, LoopInfo &LI);
104void simplifyLoopAfterUnroll(Loop *L, bool SimplifyIVs, LoopInfo *LI,
106 AssumptionCache *AC,
108 AAResults *AA = nullptr);
115 llvm::OptimizationRemarkEmitter &ORE, int OptLevel,
116 std::optional<unsigned> UserThreshold, std::optional<unsigned> UserCount,
117 std::optional<bool> UserAllowPartial, std::optional<bool> UserRuntime,
118 std::optional<bool> UserUpperBound,
119 std::optional<unsigned> UserFullUnrollMaxCount);
121/// Produce an estimate of the unrolled cost of the specified loop. This
122/// is used to a) produce a cost estimate for partial unrolling and b) to
123/// cheaply estimate cost for full unrolling when we don't want to symbolically
124/// evaluate all iterations.
126 InstructionCost LoopSize;
127 bool NotDuplicatable;
134 const SmallPtrSetImpl<const Value *> &EphValues,
135 unsigned BEInsns);
137 /// Whether it is legal to unroll this loop.
138 bool canUnroll() const { return LoopSize.isValid() && !NotDuplicatable; }
140 uint64_t getRolledLoopSize() const { return *LoopSize.getValue(); }
142 /// Returns loop size estimation for unrolled loop, given the unrolling
143 /// configuration specified by UP.
146 unsigned CountOverwrite = 0) const;
149bool computeUnrollCount(Loop *L, const TargetTransformInfo &TTI,
150 DominatorTree &DT, LoopInfo *LI, AssumptionCache *AC,
151 ScalarEvolution &SE,
152 const SmallPtrSetImpl<const Value *> &EphValues,
153 OptimizationRemarkEmitter *ORE, unsigned TripCount,
154 unsigned MaxTripCount, bool MaxOrZero,
155 unsigned TripMultiple, const UnrollCostEstimator &UCE,
156 TargetTransformInfo::UnrollingPreferences &UP,
157 TargetTransformInfo::PeelingPreferences &PP,
158 bool &UseUpperBound);
160} // end namespace llvm
This file defines the DenseMap class.
std::string Name
This file defines an InstructionCost class that is used when calculating the cost of an instruction,...
This pass exposes codegen information to IR-level passes.
A cache of @llvm.assume calls within a function.
LLVM Basic Block Representation.
Definition: BasicBlock.h:60
BlockFrequencyInfo pass uses BlockFrequencyInfoImpl implementation to estimate IR basic block frequen...
DependenceInfo - This class is the main dependence-analysis driver.
Concrete subclass of DominatorTreeBase that is used to compute a normal dominator tree.
Definition: Dominators.h:162
std::optional< CostType > getValue() const
This function is intended to be used as sparingly as possible, since the class provides the full rang...
Represents a single loop in the control flow graph.
Definition: LoopInfo.h:44
Metadata node.
Definition: Metadata.h:1067
The optimization diagnostic interface.
Analysis providing profile information.
The main scalar evolution driver.
A templated base class for SmallPtrSet which provides the typesafe interface that is common across al...
Definition: SmallPtrSet.h:321
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:50
This pass provides access to the codegen interfaces that are needed for IR-level transformations.
Produce an estimate of the unrolled cost of the specified loop.
Definition: UnrollLoop.h:125
uint64_t getUnrolledLoopSize(const TargetTransformInfo::UnrollingPreferences &UP, unsigned CountOverwrite=0) const
Returns loop size estimation for unrolled loop, given the unrolling configuration specified by UP.
bool canUnroll() const
Whether it is legal to unroll this loop.
Definition: UnrollLoop.h:138
uint64_t getRolledLoopSize() const
Definition: UnrollLoop.h:140
@ BasicBlock
Various leaf nodes.
Definition: ISDOpcodes.h:71
This is an optimization pass for GlobalISel generic memory operations.
Definition: AddressRanges.h:18
bool isSafeToUnrollAndJam(Loop *L, ScalarEvolution &SE, DominatorTree &DT, DependenceInfo &DI, LoopInfo &LI)
void simplifyLoopAfterUnroll(Loop *L, bool SimplifyIVs, LoopInfo *LI, ScalarEvolution *SE, DominatorTree *DT, AssumptionCache *AC, const TargetTransformInfo *TTI, AAResults *AA=nullptr)
Perform some cleanup and simplifications on loops after unrolling.
Definition: LoopUnroll.cpp:344
Represents the result of a UnrollLoop invocation.
Definition: UnrollLoop.h:55
@ PartiallyUnrolled
The loop was partially unrolled – we still have a loop, but with a smaller trip count.
@ Unmodified
The loop was not modified.
@ FullyUnrolled
The loop was fully unrolled into straight-line code.
bool computeUnrollCount(Loop *L, const TargetTransformInfo &TTI, DominatorTree &DT, LoopInfo *LI, AssumptionCache *AC, ScalarEvolution &SE, const SmallPtrSetImpl< const Value * > &EphValues, OptimizationRemarkEmitter *ORE, unsigned TripCount, unsigned MaxTripCount, bool MaxOrZero, unsigned TripMultiple, const UnrollCostEstimator &UCE, TargetTransformInfo::UnrollingPreferences &UP, TargetTransformInfo::PeelingPreferences &PP, bool &UseUpperBound)
const char *const LLVMLoopUnrollFollowupAll
Definition: UnrollLoop.h:43
TargetTransformInfo TTI
TargetTransformInfo::UnrollingPreferences gatherUnrollingPreferences(Loop *L, ScalarEvolution &SE, const TargetTransformInfo &TTI, BlockFrequencyInfo *BFI, ProfileSummaryInfo *PSI, llvm::OptimizationRemarkEmitter &ORE, int OptLevel, std::optional< unsigned > UserThreshold, std::optional< unsigned > UserCount, std::optional< bool > UserAllowPartial, std::optional< bool > UserRuntime, std::optional< bool > UserUpperBound, std::optional< unsigned > UserFullUnrollMaxCount)
Gather the various unrolling parameters based on the defaults, compiler flags, TTI overrides and user...
const char *const LLVMLoopUnrollFollowupRemainder
Definition: UnrollLoop.h:46
const Loop * addClonedBlockToLoopInfo(BasicBlock *OriginalBB, BasicBlock *ClonedBB, LoopInfo *LI, NewLoopsMap &NewLoops)
Adds ClonedBB to LoopInfo, creates a new loop for ClonedBB if necessary and adds a mapping from the o...
Definition: LoopUnroll.cpp:150
const char *const LLVMLoopUnrollFollowupUnrolled
Definition: UnrollLoop.h:44
LoopUnrollResult UnrollAndJamLoop(Loop *L, unsigned Count, unsigned TripCount, unsigned TripMultiple, bool UnrollRemainder, LoopInfo *LI, ScalarEvolution *SE, DominatorTree *DT, AssumptionCache *AC, const TargetTransformInfo *TTI, OptimizationRemarkEmitter *ORE, Loop **EpilogueLoop=nullptr)
MDNode * GetUnrollMetadata(MDNode *LoopID, StringRef Name)
Given an llvm.loop loop id metadata node, returns the loop hint metadata node with the given name (fo...
bool UnrollRuntimeLoopRemainder(Loop *L, unsigned Count, bool AllowExpensiveTripCount, bool UseEpilogRemainder, bool UnrollRemainder, bool ForgetAllSCEV, LoopInfo *LI, ScalarEvolution *SE, DominatorTree *DT, AssumptionCache *AC, const TargetTransformInfo *TTI, bool PreserveLCSSA, Loop **ResultLoop=nullptr)
Insert code in the prolog/epilog code when unrolling a loop with a run-time trip-count.
LoopUnrollResult UnrollLoop(Loop *L, UnrollLoopOptions ULO, LoopInfo *LI, ScalarEvolution *SE, DominatorTree *DT, AssumptionCache *AC, const llvm::TargetTransformInfo *TTI, OptimizationRemarkEmitter *ORE, bool PreserveLCSSA, Loop **RemainderLoop=nullptr, AAResults *AA=nullptr)
Unroll the given loop by Count.
Definition: LoopUnroll.cpp:440
Parameters that control the generic loop unrolling transformation.