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 BasicBlock;
26class BlockFrequencyInfo;
27class DependenceInfo;
28class DominatorTree;
29class Loop;
30class LoopInfo;
31class MDNode;
32class ProfileSummaryInfo;
33class OptimizationRemarkEmitter;
34class ScalarEvolution;
35class StringRef;
36class Value;
40/// @{
41/// Metadata attribute names
42const char *const LLVMLoopUnrollFollowupAll = "llvm.loop.unroll.followup_all";
44 "llvm.loop.unroll.followup_unrolled";
46 "llvm.loop.unroll.followup_remainder";
47/// @}
50 BasicBlock *ClonedBB, LoopInfo *LI,
51 NewLoopsMap &NewLoops);
53/// Represents the result of a \c UnrollLoop invocation.
54enum class LoopUnrollResult {
55 /// The loop was not modified.
58 /// The loop was partially unrolled -- we still have a loop, but with a
59 /// smaller trip count. We may also have emitted epilogue loop if the loop
60 /// had a non-constant trip count.
63 /// The loop was fully unrolled into straight-line code. We no longer have
64 /// any back-edges.
69 unsigned Count;
70 bool Force;
71 bool Runtime;
81 OptimizationRemarkEmitter *ORE, bool PreserveLCSSA,
82 Loop **RemainderLoop = nullptr);
85 Loop *L, unsigned Count, bool AllowExpensiveTripCount,
86 bool UseEpilogRemainder, bool UnrollRemainder, bool ForgetAllSCEV,
88 const TargetTransformInfo *TTI, bool PreserveLCSSA,
89 Loop **ResultLoop = nullptr);
91LoopUnrollResult UnrollAndJamLoop(Loop *L, unsigned Count, unsigned TripCount,
92 unsigned TripMultiple, bool UnrollRemainder,
97 Loop **EpilogueLoop = nullptr);
100 DependenceInfo &DI, LoopInfo &LI);
102void simplifyLoopAfterUnroll(Loop *L, bool SimplifyIVs, LoopInfo *LI,
104 AssumptionCache *AC,
105 const TargetTransformInfo *TTI);
112 llvm::OptimizationRemarkEmitter &ORE, int OptLevel,
113 std::optional<unsigned> UserThreshold, std::optional<unsigned> UserCount,
114 std::optional<bool> UserAllowPartial, std::optional<bool> UserRuntime,
115 std::optional<bool> UserUpperBound,
116 std::optional<unsigned> UserFullUnrollMaxCount);
118/// Produce an estimate of the unrolled cost of the specified loop. This
119/// is used to a) produce a cost estimate for partial unrolling and b) to
120/// cheaply estimate cost for full unrolling when we don't want to symbolically
121/// evaluate all iterations.
123 InstructionCost LoopSize;
124 bool NotDuplicatable;
131 const SmallPtrSetImpl<const Value *> &EphValues,
132 unsigned BEInsns);
134 /// Whether it is legal to unroll this loop.
135 bool canUnroll() const { return LoopSize.isValid() && !NotDuplicatable; }
137 uint64_t getRolledLoopSize() const { return *LoopSize.getValue(); }
139 /// Returns loop size estimation for unrolled loop, given the unrolling
140 /// configuration specified by UP.
143 unsigned CountOverwrite = 0) const;
146bool computeUnrollCount(Loop *L, const TargetTransformInfo &TTI,
147 DominatorTree &DT, LoopInfo *LI, AssumptionCache *AC,
148 ScalarEvolution &SE,
149 const SmallPtrSetImpl<const Value *> &EphValues,
150 OptimizationRemarkEmitter *ORE, unsigned TripCount,
151 unsigned MaxTripCount, bool MaxOrZero,
152 unsigned TripMultiple, const UnrollCostEstimator &UCE,
153 TargetTransformInfo::UnrollingPreferences &UP,
154 TargetTransformInfo::PeelingPreferences &PP,
155 bool &UseUpperBound);
157} // 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:122
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:135
uint64_t getRolledLoopSize() const
Definition: UnrollLoop.h:137
@ 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)
Represents the result of a UnrollLoop invocation.
Definition: UnrollLoop.h:54
@ 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:42
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:45
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:147
const char *const LLVMLoopUnrollFollowupUnrolled
Definition: UnrollLoop.h:43
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)
Unroll the given loop by Count.
Definition: LoopUnroll.cpp:295
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)
void simplifyLoopAfterUnroll(Loop *L, bool SimplifyIVs, LoopInfo *LI, ScalarEvolution *SE, DominatorTree *DT, AssumptionCache *AC, const TargetTransformInfo *TTI)
Perform some cleanup and simplifications on loops after unrolling.
Definition: LoopUnroll.cpp:215
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...
Definition: LoopUnroll.cpp:927
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.
Parameters that control the generic loop unrolling transformation.