[llvm] r342495 - [PGO][CHR] Add opt remarks.
Hiroshi Yamauchi via llvm-commits
llvm-commits at lists.llvm.org
Tue Sep 18 09:50:10 PDT 2018
Author: yamauchi
Date: Tue Sep 18 09:50:10 2018
New Revision: 342495
URL: http://llvm.org/viewvc/llvm-project?rev=342495&view=rev
Log:
[PGO][CHR] Add opt remarks.
Reviewers: davidxl
Reviewed By: davidxl
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D52056
Modified:
llvm/trunk/lib/Transforms/Instrumentation/ControlHeightReduction.cpp
Modified: llvm/trunk/lib/Transforms/Instrumentation/ControlHeightReduction.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/ControlHeightReduction.cpp?rev=342495&r1=342494&r2=342495&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/ControlHeightReduction.cpp (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/ControlHeightReduction.cpp Tue Sep 18 09:50:10 2018
@@ -19,6 +19,7 @@
#include "llvm/ADT/StringSet.h"
#include "llvm/Analysis/BlockFrequencyInfo.h"
#include "llvm/Analysis/GlobalsModRef.h"
+#include "llvm/Analysis/OptimizationRemarkEmitter.h"
#include "llvm/Analysis/ProfileSummaryInfo.h"
#include "llvm/Analysis/RegionInfo.h"
#include "llvm/Analysis/RegionIterator.h"
@@ -320,8 +321,9 @@ class CHRScope {
class CHR {
public:
CHR(Function &Fin, BlockFrequencyInfo &BFIin, DominatorTree &DTin,
- ProfileSummaryInfo &PSIin, RegionInfo &RIin)
- : F(Fin), BFI(BFIin), DT(DTin), PSI(PSIin), RI(RIin) {}
+ ProfileSummaryInfo &PSIin, RegionInfo &RIin,
+ OptimizationRemarkEmitter &OREin)
+ : F(Fin), BFI(BFIin), DT(DTin), PSI(PSIin), RI(RIin), ORE(OREin) {}
~CHR() {
for (CHRScope *Scope : Scopes) {
@@ -403,6 +405,7 @@ class CHR {
DominatorTree &DT;
ProfileSummaryInfo Ψ
RegionInfo &RI;
+ OptimizationRemarkEmitter &ORE;
CHRStats Stats;
// All the true-biased regions in the function
@@ -771,6 +774,12 @@ CHRScope * CHR::findScope(Region *R) {
Scopes.insert(Result);
CHR_DEBUG(dbgs() << "Found a region with a branch\n");
++Stats.NumBranches;
+ if (!RI.HasBranch) {
+ ORE.emit([&]() {
+ return OptimizationRemarkMissed(DEBUG_TYPE, "BranchNotBiased", BI)
+ << "Branch not biased";
+ });
+ }
}
}
}
@@ -811,6 +820,11 @@ CHRScope * CHR::findScope(Region *R) {
FalseBiasedSelectsGlobal,
SelectBiasMap))
RI.Selects.push_back(SI);
+ else
+ ORE.emit([&]() {
+ return OptimizationRemarkMissed(DEBUG_TYPE, "SelectNotBiased", SI)
+ << "Select not biased";
+ });
};
if (!Result) {
CHR_DEBUG(dbgs() << "Found a select-only region\n");
@@ -882,6 +896,11 @@ void CHR::checkScopeHoistable(CHRScope *
DT, Unhoistables, nullptr);
if (!IsHoistable) {
CHR_DEBUG(dbgs() << "Dropping select " << *SI << "\n");
+ ORE.emit([&]() {
+ return OptimizationRemarkMissed(DEBUG_TYPE,
+ "DropUnhoistableSelect", SI)
+ << "Dropped unhoistable select";
+ });
it = Selects.erase(it);
// Since we are dropping the select here, we also drop it from
// Unhoistables.
@@ -905,6 +924,13 @@ void CHR::checkScopeHoistable(CHRScope *
for (SelectInst *SI : Selects) {
dbgs() << "SI " << *SI << "\n";
});
+ for (SelectInst *SI : Selects) {
+ ORE.emit([&]() {
+ return OptimizationRemarkMissed(DEBUG_TYPE,
+ "DropSelectUnhoistableBranch", SI)
+ << "Dropped select due to unhoistable branch";
+ });
+ }
Selects.erase(std::remove_if(Selects.begin(), Selects.end(),
[EntryBB](SelectInst *SI) {
return SI->getParent() == EntryBB;
@@ -1133,6 +1159,13 @@ SmallVector<CHRScope *, 8> CHR::splitSco
ConditionValues, DT, Unhoistables)) {
PrevConditionValues = ConditionValues;
PrevInsertPoint = InsertPoint;
+ ORE.emit([&]() {
+ return OptimizationRemarkMissed(DEBUG_TYPE,
+ "SplitScopeFromOuter",
+ RI.R->getEntry()->getTerminator())
+ << "Split scope from outer due to unhoistable branch/select "
+ << "and/or lack of common condition values";
+ });
} else {
// Not splitting from the outer. Use the outer bases and insert
// point. Union the bases.
@@ -1162,6 +1195,13 @@ SmallVector<CHRScope *, 8> CHR::splitSco
PrevConditionValues = ConditionValues;
PrevInsertPoint = InsertPoint;
PrevSplitFromOuter = true;
+ ORE.emit([&]() {
+ return OptimizationRemarkMissed(DEBUG_TYPE,
+ "SplitScopeFromPrev",
+ RI.R->getEntry()->getTerminator())
+ << "Split scope from previous due to unhoistable branch/select "
+ << "and/or lack of common condition values";
+ });
} else {
// Not splitting. Union the bases. Keep the hoist point.
PrevConditionValues.insert(ConditionValues.begin(), ConditionValues.end());
@@ -1283,6 +1323,15 @@ void CHR::filterScopes(SmallVectorImpl<C
<< " falsy-regions " << Scope->FalseBiasedRegions.size()
<< " true-selects " << Scope->TrueBiasedSelects.size()
<< " false-selects " << Scope->FalseBiasedSelects.size() << "\n");
+ ORE.emit([&]() {
+ return OptimizationRemarkMissed(
+ DEBUG_TYPE,
+ "DropScopeWithOneBranchOrSelect",
+ Scope->RegInfos[0].R->getEntry()->getTerminator())
+ << "Drop scope with < "
+ << ore::NV("CHRMergeThreshold", CHRMergeThreshold)
+ << " biased branch(es) or select(s)";
+ });
continue;
}
Output.push_back(Scope);
@@ -1773,6 +1822,14 @@ void CHR::fixupBranchesAndSelects(CHRSco
}
Stats.NumBranchesDelta += NumCHRedBranches - 1;
Stats.WeightedNumBranchesDelta += (NumCHRedBranches - 1) * ProfileCount;
+ ORE.emit([&]() {
+ return OptimizationRemark(DEBUG_TYPE,
+ "CHR",
+ // Refer to the hot (original) path
+ MergedBR->getSuccessor(0)->getTerminator())
+ << "Merged " << ore::NV("NumCHRedBranches", NumCHRedBranches)
+ << " branches or selects";
+ });
MergedBR->setCondition(MergedCondition);
SmallVector<uint32_t, 2> Weights;
Weights.push_back(static_cast<uint32_t>(CHRBranchBias.scale(1000)));
@@ -1961,8 +2018,18 @@ bool CHR::run() {
}
}
- if (Changed)
+ if (Changed) {
CHR_DEBUG(dumpIR(F, "after", &Stats));
+ ORE.emit([&]() {
+ return OptimizationRemark(DEBUG_TYPE, "Stats", &F)
+ << ore::NV("Function", &F) << " "
+ << "Reduced the number of branches in hot paths by "
+ << ore::NV("NumBranchesDelta", Stats.NumBranchesDelta)
+ << " (static) and "
+ << ore::NV("WeightedNumBranchesDelta", Stats.WeightedNumBranchesDelta)
+ << " (weighted by PGO count)";
+ });
+ }
return Changed;
}
@@ -1974,7 +2041,9 @@ bool ControlHeightReductionLegacyPass::r
ProfileSummaryInfo &PSI =
*getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI();
RegionInfo &RI = getAnalysis<RegionInfoPass>().getRegionInfo();
- return CHR(F, BFI, DT, PSI, RI).run();
+ std::unique_ptr<OptimizationRemarkEmitter> OwnedORE =
+ llvm::make_unique<OptimizationRemarkEmitter>(&F);
+ return CHR(F, BFI, DT, PSI, RI, *OwnedORE.get()).run();
}
namespace llvm {
@@ -1992,7 +2061,8 @@ PreservedAnalyses ControlHeightReduction
auto &MAM = MAMProxy.getManager();
auto &PSI = *MAM.getCachedResult<ProfileSummaryAnalysis>(*F.getParent());
auto &RI = FAM.getResult<RegionInfoAnalysis>(F);
- bool Changed = CHR(F, BFI, DT, PSI, RI).run();
+ auto &ORE = FAM.getResult<OptimizationRemarkEmitterAnalysis>(F);
+ bool Changed = CHR(F, BFI, DT, PSI, RI, ORE).run();
if (!Changed)
return PreservedAnalyses::all();
auto PA = PreservedAnalyses();
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