[llvm] r319794 - [PGO] detect infinite loop and form MST properly
Xinliang David Li via llvm-commits
llvm-commits at lists.llvm.org
Tue Dec 5 09:19:41 PST 2017
Author: davidxl
Date: Tue Dec 5 09:19:41 2017
New Revision: 319794
URL: http://llvm.org/viewvc/llvm-project?rev=319794&view=rev
Log:
[PGO] detect infinite loop and form MST properly
Differential Revision: http://reviews.llvm.org/D40702
Added:
llvm/trunk/test/Transforms/PGOProfile/infinite_loop_gen.ll
Modified:
llvm/trunk/lib/Transforms/Instrumentation/CFGMST.h
llvm/trunk/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
Modified: llvm/trunk/lib/Transforms/Instrumentation/CFGMST.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/CFGMST.h?rev=319794&r1=319793&r2=319794&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/CFGMST.h (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/CFGMST.h Tue Dec 5 09:19:41 2017
@@ -20,6 +20,7 @@
#include "llvm/Analysis/BlockFrequencyInfo.h"
#include "llvm/Analysis/BranchProbabilityInfo.h"
#include "llvm/Analysis/CFG.h"
+#include "llvm/Analysis/LoopInfo.h"
#include "llvm/Support/BranchProbability.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
@@ -136,6 +137,21 @@ public:
<< " w = " << BBWeight << "\n");
}
}
+ // check if there is any infinite loop. If yes, add a fake edge from
+ // the header block to the fake node:
+ for (auto *L : *LI) {
+ SmallVector<BasicBlock *, 2> ExitingBlocks;
+ L->getExitingBlocks(ExitingBlocks);
+ if (!ExitingBlocks.empty())
+ continue;
+ auto *HB = L->getHeader();
+ if (!HB)
+ continue;
+ addEdge(HB, nullptr, UINT64_MAX);
+ DEBUG(dbgs() << " Edge: from infinite loop header "
+ << HB->getName() << " to exit"
+ << " w = " << UINT64_MAX << "\n");
+ }
}
// Sort CFG edges based on its weight.
@@ -212,11 +228,13 @@ public:
BranchProbabilityInfo *BPI;
BlockFrequencyInfo *BFI;
+ LoopInfo *LI;
public:
CFGMST(Function &Func, BranchProbabilityInfo *BPI_ = nullptr,
- BlockFrequencyInfo *BFI_ = nullptr)
- : F(Func), BPI(BPI_), BFI(BFI_) {
+ BlockFrequencyInfo *BFI_ = nullptr,
+ LoopInfo *LI_ = nullptr)
+ : F(Func), BPI(BPI_), BFI(BFI_), LI(LI_) {
buildEdges();
sortEdgesByWeight();
computeMinimumSpanningTree();
Modified: llvm/trunk/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/Instrumentation/PGOInstrumentation.cpp?rev=319794&r1=319793&r2=319794&view=diff
==============================================================================
--- llvm/trunk/lib/Transforms/Instrumentation/PGOInstrumentation.cpp (original)
+++ llvm/trunk/lib/Transforms/Instrumentation/PGOInstrumentation.cpp Tue Dec 5 09:19:41 2017
@@ -390,6 +390,7 @@ private:
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequired<BlockFrequencyInfoWrapperPass>();
+ AU.addRequired<LoopInfoWrapperPass>();
}
};
@@ -415,6 +416,7 @@ private:
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequired<BlockFrequencyInfoWrapperPass>();
+ AU.addRequired<LoopInfoWrapperPass>();
}
};
@@ -426,6 +428,7 @@ INITIALIZE_PASS_BEGIN(PGOInstrumentation
"PGO instrumentation.", false, false)
INITIALIZE_PASS_DEPENDENCY(BlockFrequencyInfoWrapperPass)
INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfoWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
INITIALIZE_PASS_END(PGOInstrumentationGenLegacyPass, "pgo-instr-gen",
"PGO instrumentation.", false, false)
@@ -439,6 +442,7 @@ INITIALIZE_PASS_BEGIN(PGOInstrumentation
"Read PGO instrumentation profile.", false, false)
INITIALIZE_PASS_DEPENDENCY(BlockFrequencyInfoWrapperPass)
INITIALIZE_PASS_DEPENDENCY(BranchProbabilityInfoWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
INITIALIZE_PASS_END(PGOInstrumentationUseLegacyPass, "pgo-instr-use",
"Read PGO instrumentation profile.", false, false)
@@ -530,9 +534,9 @@ public:
Function &Func,
std::unordered_multimap<Comdat *, GlobalValue *> &ComdatMembers,
bool CreateGlobalVar = false, BranchProbabilityInfo *BPI = nullptr,
- BlockFrequencyInfo *BFI = nullptr)
+ BlockFrequencyInfo *BFI = nullptr, LoopInfo *LI = nullptr)
: F(Func), ComdatMembers(ComdatMembers), ValueSites(IPVK_Last + 1),
- SIVisitor(Func), MIVisitor(Func), MST(F, BPI, BFI) {
+ SIVisitor(Func), MIVisitor(Func), MST(F, BPI, BFI, LI) {
// This should be done before CFG hash computation.
SIVisitor.countSelects(Func);
MIVisitor.countMemIntrinsics(Func);
@@ -715,9 +719,10 @@ BasicBlock *FuncPGOInstrumentation<Edge,
// Critical edges will be split.
static void instrumentOneFunc(
Function &F, Module *M, BranchProbabilityInfo *BPI, BlockFrequencyInfo *BFI,
+ LoopInfo *LI,
std::unordered_multimap<Comdat *, GlobalValue *> &ComdatMembers) {
FuncPGOInstrumentation<PGOEdge, BBInfo> FuncInfo(F, ComdatMembers, true, BPI,
- BFI);
+ BFI, LI);
unsigned NumCounters = FuncInfo.getNumCounters();
uint32_t I = 0;
@@ -844,9 +849,10 @@ public:
PGOUseFunc(Function &Func, Module *Modu,
std::unordered_multimap<Comdat *, GlobalValue *> &ComdatMembers,
BranchProbabilityInfo *BPI = nullptr,
- BlockFrequencyInfo *BFIin = nullptr)
+ BlockFrequencyInfo *BFIin = nullptr,
+ LoopInfo *LI = nullptr)
: F(Func), M(Modu), BFI(BFIin),
- FuncInfo(Func, ComdatMembers, false, BPI, BFIin),
+ FuncInfo(Func, ComdatMembers, false, BPI, BFIin, LI),
FreqAttr(FFA_Normal) {}
// Read counts for the instrumented BB from profile.
@@ -1379,7 +1385,8 @@ static void collectComdatMembers(
static bool InstrumentAllFunctions(
Module &M, function_ref<BranchProbabilityInfo *(Function &)> LookupBPI,
- function_ref<BlockFrequencyInfo *(Function &)> LookupBFI) {
+ function_ref<BlockFrequencyInfo *(Function &)> LookupBFI,
+ function_ref<LoopInfo *(Function &)> LookupLI) {
createIRLevelProfileFlagVariable(M);
std::unordered_multimap<Comdat *, GlobalValue *> ComdatMembers;
collectComdatMembers(M, ComdatMembers);
@@ -1389,7 +1396,8 @@ static bool InstrumentAllFunctions(
continue;
auto *BPI = LookupBPI(F);
auto *BFI = LookupBFI(F);
- instrumentOneFunc(F, &M, BPI, BFI, ComdatMembers);
+ auto *LI = LookupLI(F);
+ instrumentOneFunc(F, &M, BPI, BFI, LI, ComdatMembers);
}
return true;
}
@@ -1404,7 +1412,10 @@ bool PGOInstrumentationGenLegacyPass::ru
auto LookupBFI = [this](Function &F) {
return &this->getAnalysis<BlockFrequencyInfoWrapperPass>(F).getBFI();
};
- return InstrumentAllFunctions(M, LookupBPI, LookupBFI);
+ auto LookupLI = [this](Function &F) {
+ return &this->getAnalysis<LoopInfoWrapperPass>(F).getLoopInfo();
+ };
+ return InstrumentAllFunctions(M, LookupBPI, LookupBFI, LookupLI);
}
PreservedAnalyses PGOInstrumentationGen::run(Module &M,
@@ -1418,7 +1429,11 @@ PreservedAnalyses PGOInstrumentationGen:
return &FAM.getResult<BlockFrequencyAnalysis>(F);
};
- if (!InstrumentAllFunctions(M, LookupBPI, LookupBFI))
+ auto LookupLI = [&FAM](Function &F) {
+ return &FAM.getResult<LoopAnalysis>(F);
+ };
+
+ if (!InstrumentAllFunctions(M, LookupBPI, LookupBFI, LookupLI))
return PreservedAnalyses::all();
return PreservedAnalyses::none();
@@ -1427,7 +1442,8 @@ PreservedAnalyses PGOInstrumentationGen:
static bool annotateAllFunctions(
Module &M, StringRef ProfileFileName,
function_ref<BranchProbabilityInfo *(Function &)> LookupBPI,
- function_ref<BlockFrequencyInfo *(Function &)> LookupBFI) {
+ function_ref<BlockFrequencyInfo *(Function &)> LookupBFI,
+ function_ref<LoopInfo *(Function &)> LookupLI) {
DEBUG(dbgs() << "Read in profile counters: ");
auto &Ctx = M.getContext();
// Read the counter array from file.
@@ -1463,7 +1479,8 @@ static bool annotateAllFunctions(
continue;
auto *BPI = LookupBPI(F);
auto *BFI = LookupBFI(F);
- PGOUseFunc Func(F, &M, ComdatMembers, BPI, BFI);
+ auto *LI = LookupLI(F);
+ PGOUseFunc Func(F, &M, ComdatMembers, BPI, BFI, LI);
if (!Func.readCounters(PGOReader.get()))
continue;
Func.populateCounters();
@@ -1539,7 +1556,11 @@ PreservedAnalyses PGOInstrumentationUse:
return &FAM.getResult<BlockFrequencyAnalysis>(F);
};
- if (!annotateAllFunctions(M, ProfileFileName, LookupBPI, LookupBFI))
+ auto LookupLI = [&FAM](Function &F) {
+ return &FAM.getResult<LoopAnalysis>(F);
+ };
+
+ if (!annotateAllFunctions(M, ProfileFileName, LookupBPI, LookupBFI, LookupLI))
return PreservedAnalyses::all();
return PreservedAnalyses::none();
@@ -1555,8 +1576,11 @@ bool PGOInstrumentationUseLegacyPass::ru
auto LookupBFI = [this](Function &F) {
return &this->getAnalysis<BlockFrequencyInfoWrapperPass>(F).getBFI();
};
+ auto LookupLI = [this](Function &F) {
+ return &this->getAnalysis<LoopInfoWrapperPass>(F).getLoopInfo();
+ };
- return annotateAllFunctions(M, ProfileFileName, LookupBPI, LookupBFI);
+ return annotateAllFunctions(M, ProfileFileName, LookupBPI, LookupBFI, LookupLI);
}
static std::string getSimpleNodeName(const BasicBlock *Node) {
Added: llvm/trunk/test/Transforms/PGOProfile/infinite_loop_gen.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/PGOProfile/infinite_loop_gen.ll?rev=319794&view=auto
==============================================================================
--- llvm/trunk/test/Transforms/PGOProfile/infinite_loop_gen.ll (added)
+++ llvm/trunk/test/Transforms/PGOProfile/infinite_loop_gen.ll Tue Dec 5 09:19:41 2017
@@ -0,0 +1,18 @@
+; RUN: opt < %s -pgo-instr-gen -S -o - | FileCheck %s
+
+define void @foo() {
+entry:
+ br label %while.body
+; CHECK: llvm.instrprof.increment
+
+ while.body: ; preds = %entry, %while.body
+; CHECK: llvm.instrprof.increment
+ call void (...) @bar() #2
+ br label %while.body
+}
+
+declare void @bar(...)
+
+
+attributes #0 = { nounwind }
+
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