[PGO] Profile guided code size optimization.
Summary:
Enable some of the existing size optimizations for cold code under PGO.
A ~5% code size saving in big internal app under PGO.
The way it gets BFI/PSI is discussed in the RFC thread
http://lists.llvm.org/pipermail/llvm-dev/2019-March/130894.html
Note it doesn't currently touch loop passes.
Reviewers: davidxl, eraman
Reviewed By: eraman
Subscribers: mgorny, javed.absar, smeenai, mehdi_amini, eraman, zzheng, steven_wu, dexonsmith, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D59514
llvm-svn: 358422
diff --git a/llvm/lib/Transforms/Scalar/ConstantHoisting.cpp b/llvm/lib/Transforms/Scalar/ConstantHoisting.cpp
index f1cc5e4..683cf32 100644
--- a/llvm/lib/Transforms/Scalar/ConstantHoisting.cpp
+++ b/llvm/lib/Transforms/Scalar/ConstantHoisting.cpp
@@ -41,6 +41,7 @@
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/BlockFrequencyInfo.h"
+#include "llvm/Analysis/ProfileSummaryInfo.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/Transforms/Utils/Local.h"
#include "llvm/IR/BasicBlock.h"
@@ -60,6 +61,7 @@
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Utils/SizeOpts.h"
#include <algorithm>
#include <cassert>
#include <cstdint>
@@ -111,6 +113,7 @@
if (ConstHoistWithBlockFrequency)
AU.addRequired<BlockFrequencyInfoWrapperPass>();
AU.addRequired<DominatorTreeWrapperPass>();
+ AU.addRequired<ProfileSummaryInfoWrapperPass>();
AU.addRequired<TargetTransformInfoWrapperPass>();
}
@@ -126,6 +129,7 @@
"Constant Hoisting", false, false)
INITIALIZE_PASS_DEPENDENCY(BlockFrequencyInfoWrapperPass)
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(ProfileSummaryInfoWrapperPass)
INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)
INITIALIZE_PASS_END(ConstantHoistingLegacyPass, "consthoist",
"Constant Hoisting", false, false)
@@ -148,7 +152,8 @@
ConstHoistWithBlockFrequency
? &getAnalysis<BlockFrequencyInfoWrapperPass>().getBFI()
: nullptr,
- Fn.getEntryBlock());
+ Fn.getEntryBlock(),
+ &getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI());
if (MadeChange) {
LLVM_DEBUG(dbgs() << "********** Function after Constant Hoisting: "
@@ -548,7 +553,9 @@
ConstCandVecType::iterator &MaxCostItr) {
unsigned NumUses = 0;
- if(!Entry->getParent()->hasOptSize() || std::distance(S,E) > 100) {
+ bool OptForSize = Entry->getParent()->hasOptSize() ||
+ llvm::shouldOptimizeForSize(Entry->getParent(), PSI, BFI);
+ if (!OptForSize || std::distance(S,E) > 100) {
for (auto ConstCand = S; ConstCand != E; ++ConstCand) {
NumUses += ConstCand->Uses.size();
if (ConstCand->CumulativeCost > MaxCostItr->CumulativeCost)
@@ -919,13 +926,14 @@
/// Optimize expensive integer constants in the given function.
bool ConstantHoistingPass::runImpl(Function &Fn, TargetTransformInfo &TTI,
DominatorTree &DT, BlockFrequencyInfo *BFI,
- BasicBlock &Entry) {
+ BasicBlock &Entry, ProfileSummaryInfo *PSI) {
this->TTI = &TTI;
this->DT = &DT;
this->BFI = BFI;
this->DL = &Fn.getParent()->getDataLayout();
this->Ctx = &Fn.getContext();
this->Entry = &Entry;
+ this->PSI = PSI;
// Collect all constant candidates.
collectConstantCandidates(Fn);
@@ -962,7 +970,9 @@
auto BFI = ConstHoistWithBlockFrequency
? &AM.getResult<BlockFrequencyAnalysis>(F)
: nullptr;
- if (!runImpl(F, TTI, DT, BFI, F.getEntryBlock()))
+ auto &MAM = AM.getResult<ModuleAnalysisManagerFunctionProxy>(F).getManager();
+ auto *PSI = MAM.getCachedResult<ProfileSummaryAnalysis>(*F.getParent());
+ if (!runImpl(F, TTI, DT, BFI, F.getEntryBlock(), PSI))
return PreservedAnalyses::all();
PreservedAnalyses PA;
diff --git a/llvm/lib/Transforms/Scalar/LoopLoadElimination.cpp b/llvm/lib/Transforms/Scalar/LoopLoadElimination.cpp
index 7526610..68bb28d 100644
--- a/llvm/lib/Transforms/Scalar/LoopLoadElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopLoadElimination.cpp
@@ -29,11 +29,14 @@
#include "llvm/ADT/Statistic.h"
#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Analysis/AssumptionCache.h"
+#include "llvm/Analysis/BlockFrequencyInfo.h"
#include "llvm/Analysis/GlobalsModRef.h"
+#include "llvm/Analysis/LazyBlockFrequencyInfo.h"
#include "llvm/Analysis/LoopAccessAnalysis.h"
#include "llvm/Analysis/LoopAnalysisManager.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/MemorySSA.h"
+#include "llvm/Analysis/ProfileSummaryInfo.h"
#include "llvm/Analysis/ScalarEvolution.h"
#include "llvm/Analysis/ScalarEvolutionExpander.h"
#include "llvm/Analysis/ScalarEvolutionExpressions.h"
@@ -54,6 +57,7 @@
#include "llvm/Transforms/Scalar.h"
#include "llvm/Transforms/Utils.h"
#include "llvm/Transforms/Utils/LoopVersioning.h"
+#include "llvm/Transforms/Utils/SizeOpts.h"
#include <algorithm>
#include <cassert>
#include <forward_list>
@@ -159,8 +163,9 @@
class LoadEliminationForLoop {
public:
LoadEliminationForLoop(Loop *L, LoopInfo *LI, const LoopAccessInfo &LAI,
- DominatorTree *DT)
- : L(L), LI(LI), LAI(LAI), DT(DT), PSE(LAI.getPSE()) {}
+ DominatorTree *DT, BlockFrequencyInfo *BFI,
+ ProfileSummaryInfo* PSI)
+ : L(L), LI(LI), LAI(LAI), DT(DT), BFI(BFI), PSI(PSI), PSE(LAI.getPSE()) {}
/// Look through the loop-carried and loop-independent dependences in
/// this loop and find store->load dependences.
@@ -529,7 +534,11 @@
}
if (!Checks.empty() || !LAI.getPSE().getUnionPredicate().isAlwaysTrue()) {
- if (L->getHeader()->getParent()->hasOptSize()) {
+ auto *HeaderBB = L->getHeader();
+ auto *F = HeaderBB->getParent();
+ bool OptForSize = F->hasOptSize() ||
+ llvm::shouldOptimizeForSize(HeaderBB, PSI, BFI);
+ if (OptForSize) {
LLVM_DEBUG(
dbgs() << "Versioning is needed but not allowed when optimizing "
"for size.\n");
@@ -572,6 +581,8 @@
LoopInfo *LI;
const LoopAccessInfo &LAI;
DominatorTree *DT;
+ BlockFrequencyInfo *BFI;
+ ProfileSummaryInfo *PSI;
PredicatedScalarEvolution PSE;
};
@@ -579,6 +590,7 @@
static bool
eliminateLoadsAcrossLoops(Function &F, LoopInfo &LI, DominatorTree &DT,
+ BlockFrequencyInfo *BFI, ProfileSummaryInfo *PSI,
function_ref<const LoopAccessInfo &(Loop &)> GetLAI) {
// Build up a worklist of inner-loops to transform to avoid iterator
// invalidation.
@@ -597,7 +609,7 @@
bool Changed = false;
for (Loop *L : Worklist) {
// The actual work is performed by LoadEliminationForLoop.
- LoadEliminationForLoop LEL(L, &LI, GetLAI(*L), &DT);
+ LoadEliminationForLoop LEL(L, &LI, GetLAI(*L), &DT, BFI, PSI);
Changed |= LEL.processLoop();
}
return Changed;
@@ -622,10 +634,14 @@
auto &LI = getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
auto &LAA = getAnalysis<LoopAccessLegacyAnalysis>();
auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
+ auto *PSI = &getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI();
+ auto *BFI = (PSI && PSI->hasProfileSummary()) ?
+ &getAnalysis<LazyBlockFrequencyInfoPass>().getBFI() :
+ nullptr;
// Process each loop nest in the function.
return eliminateLoadsAcrossLoops(
- F, LI, DT,
+ F, LI, DT, BFI, PSI,
[&LAA](Loop &L) -> const LoopAccessInfo & { return LAA.getInfo(&L); });
}
@@ -638,6 +654,8 @@
AU.addRequired<DominatorTreeWrapperPass>();
AU.addPreserved<DominatorTreeWrapperPass>();
AU.addPreserved<GlobalsAAWrapperPass>();
+ AU.addRequired<ProfileSummaryInfoWrapperPass>();
+ LazyBlockFrequencyInfoPass::getLazyBFIAnalysisUsage(AU);
}
};
@@ -653,6 +671,8 @@
INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
INITIALIZE_PASS_DEPENDENCY(ScalarEvolutionWrapperPass)
INITIALIZE_PASS_DEPENDENCY(LoopSimplify)
+INITIALIZE_PASS_DEPENDENCY(ProfileSummaryInfoWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(LazyBlockFrequencyInfoPass)
INITIALIZE_PASS_END(LoopLoadElimination, LLE_OPTION, LLE_name, false, false)
FunctionPass *llvm::createLoopLoadEliminationPass() {
@@ -668,13 +688,17 @@
auto &TLI = AM.getResult<TargetLibraryAnalysis>(F);
auto &AA = AM.getResult<AAManager>(F);
auto &AC = AM.getResult<AssumptionAnalysis>(F);
+ auto &MAM = AM.getResult<ModuleAnalysisManagerFunctionProxy>(F).getManager();
+ auto *PSI = MAM.getCachedResult<ProfileSummaryAnalysis>(*F.getParent());
+ auto *BFI = (PSI && PSI->hasProfileSummary()) ?
+ &AM.getResult<BlockFrequencyAnalysis>(F) : nullptr;
MemorySSA *MSSA = EnableMSSALoopDependency
? &AM.getResult<MemorySSAAnalysis>(F).getMSSA()
: nullptr;
auto &LAM = AM.getResult<LoopAnalysisManagerFunctionProxy>(F).getManager();
bool Changed = eliminateLoadsAcrossLoops(
- F, LI, DT, [&](Loop &L) -> const LoopAccessInfo & {
+ F, LI, DT, BFI, PSI, [&](Loop &L) -> const LoopAccessInfo & {
LoopStandardAnalysisResults AR = {AA, AC, DT, LI, SE, TLI, TTI, MSSA};
return LAM.getResult<LoopAccessAnalysis>(L, AR);
});
diff --git a/llvm/lib/Transforms/Scalar/LoopUnrollAndJamPass.cpp b/llvm/lib/Transforms/Scalar/LoopUnrollAndJamPass.cpp
index 71e9953..86891eb 100644
--- a/llvm/lib/Transforms/Scalar/LoopUnrollAndJamPass.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopUnrollAndJamPass.cpp
@@ -294,7 +294,8 @@
return LoopUnrollResult::Unmodified;
TargetTransformInfo::UnrollingPreferences UP = gatherUnrollingPreferences(
- L, SE, TTI, OptLevel, None, None, None, None, None, None);
+ L, SE, TTI, nullptr, nullptr, OptLevel,
+ None, None, None, None, None, None);
if (AllowUnrollAndJam.getNumOccurrences() > 0)
UP.UnrollAndJam = AllowUnrollAndJam;
if (UnrollAndJamThreshold.getNumOccurrences() > 0)
diff --git a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
index 53d4ae8..c113e4d 100644
--- a/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopUnrollPass.cpp
@@ -23,7 +23,9 @@
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Analysis/AssumptionCache.h"
+#include "llvm/Analysis/BlockFrequencyInfo.h"
#include "llvm/Analysis/CodeMetrics.h"
+#include "llvm/Analysis/LazyBlockFrequencyInfo.h"
#include "llvm/Analysis/LoopAnalysisManager.h"
#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Analysis/LoopPass.h"
@@ -55,6 +57,7 @@
#include "llvm/Transforms/Utils.h"
#include "llvm/Transforms/Utils/LoopSimplify.h"
#include "llvm/Transforms/Utils/LoopUtils.h"
+#include "llvm/Transforms/Utils/SizeOpts.h"
#include "llvm/Transforms/Utils/UnrollLoop.h"
#include <algorithm>
#include <cassert>
@@ -165,7 +168,8 @@
/// Gather the various unrolling parameters based on the defaults, compiler
/// flags, TTI overrides and user specified parameters.
TargetTransformInfo::UnrollingPreferences llvm::gatherUnrollingPreferences(
- Loop *L, ScalarEvolution &SE, const TargetTransformInfo &TTI, int OptLevel,
+ Loop *L, ScalarEvolution &SE, const TargetTransformInfo &TTI,
+ BlockFrequencyInfo *BFI, ProfileSummaryInfo *PSI, int OptLevel,
Optional<unsigned> UserThreshold, Optional<unsigned> UserCount,
Optional<bool> UserAllowPartial, Optional<bool> UserRuntime,
Optional<bool> UserUpperBound, Optional<bool> UserAllowPeeling) {
@@ -198,7 +202,9 @@
TTI.getUnrollingPreferences(L, SE, UP);
// Apply size attributes
- if (L->getHeader()->getParent()->hasOptSize()) {
+ bool OptForSize = L->getHeader()->getParent()->hasOptSize() ||
+ llvm::shouldOptimizeForSize(L->getHeader(), PSI, BFI);
+ if (OptForSize) {
UP.Threshold = UP.OptSizeThreshold;
UP.PartialThreshold = UP.PartialOptSizeThreshold;
}
@@ -963,7 +969,9 @@
static LoopUnrollResult tryToUnrollLoop(
Loop *L, DominatorTree &DT, LoopInfo *LI, ScalarEvolution &SE,
const TargetTransformInfo &TTI, AssumptionCache &AC,
- OptimizationRemarkEmitter &ORE, bool PreserveLCSSA, int OptLevel,
+ OptimizationRemarkEmitter &ORE,
+ BlockFrequencyInfo *BFI, ProfileSummaryInfo *PSI,
+ bool PreserveLCSSA, int OptLevel,
bool OnlyWhenForced, bool ForgetAllSCEV, Optional<unsigned> ProvidedCount,
Optional<unsigned> ProvidedThreshold, Optional<bool> ProvidedAllowPartial,
Optional<bool> ProvidedRuntime, Optional<bool> ProvidedUpperBound,
@@ -989,7 +997,7 @@
bool NotDuplicatable;
bool Convergent;
TargetTransformInfo::UnrollingPreferences UP = gatherUnrollingPreferences(
- L, SE, TTI, OptLevel, ProvidedThreshold, ProvidedCount,
+ L, SE, TTI, BFI, PSI, OptLevel, ProvidedThreshold, ProvidedCount,
ProvidedAllowPartial, ProvidedRuntime, ProvidedUpperBound,
ProvidedAllowPeeling);
// Exit early if unrolling is disabled.
@@ -1176,7 +1184,8 @@
bool PreserveLCSSA = mustPreserveAnalysisID(LCSSAID);
LoopUnrollResult Result = tryToUnrollLoop(
- L, DT, LI, SE, TTI, AC, ORE, PreserveLCSSA, OptLevel, OnlyWhenForced,
+ L, DT, LI, SE, TTI, AC, ORE, nullptr, nullptr,
+ PreserveLCSSA, OptLevel, OnlyWhenForced,
ForgetAllSCEV, ProvidedCount, ProvidedThreshold, ProvidedAllowPartial,
ProvidedRuntime, ProvidedUpperBound, ProvidedAllowPeeling);
@@ -1257,6 +1266,7 @@
bool Changed =
tryToUnrollLoop(&L, AR.DT, &AR.LI, AR.SE, AR.TTI, AR.AC, *ORE,
+ /*BFI*/ nullptr, /*PSI*/ nullptr,
/*PreserveLCSSA*/ true, OptLevel, OnlyWhenForced,
/*ForgetAllSCEV*/ false, /*Count*/ None,
/*Threshold*/ None, /*AllowPartial*/ false,
@@ -1359,6 +1369,8 @@
AM.getResult<ModuleAnalysisManagerFunctionProxy>(F).getManager();
ProfileSummaryInfo *PSI =
MAM.getCachedResult<ProfileSummaryAnalysis>(*F.getParent());
+ auto *BFI = (PSI && PSI->hasProfileSummary()) ?
+ &AM.getResult<BlockFrequencyAnalysis>(F) : nullptr;
bool Changed = false;
@@ -1394,7 +1406,7 @@
// The API here is quite complex to call and we allow to select some
// flavors of unrolling during construction time (by setting UnrollOpts).
LoopUnrollResult Result = tryToUnrollLoop(
- &L, DT, &LI, SE, TTI, AC, ORE,
+ &L, DT, &LI, SE, TTI, AC, ORE, BFI, PSI,
/*PreserveLCSSA*/ true, UnrollOpts.OptLevel, UnrollOpts.OnlyWhenForced,
/*ForgetAllSCEV*/ false, /*Count*/ None,
/*Threshold*/ None, UnrollOpts.AllowPartial, UnrollOpts.AllowRuntime,