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We can improve the performance (generally) by memo-izing the action to map a debug location to its function summary. 

Summary:
Here are timings (as reported by "opt -time-passes") for
sample-profile pass for some files holding hot functions from a major
service©r. Average 17% reduction. Delta column is 100*(old-new)/old.

```
Old    New    Delta
0.0537 0.0538 -0.2%
0.8155 0.6522 20.0%
0.0779 0.0751  3.6%
0.0727 0.0913 -25.6%
0.1622 0.1302 19.7%
0.0627 0.0594  5.3%
0.0766 0.0744  2.9%
0.6426 0.4387 31.7%
0.3521 0.2776 21.2%
0.3549 0.2721 23.3%
0.0912 0.0904  0.9%
0.1236 0.1059 14.3%
0.0854 0.0866 -1.4%
0.0757 0.0722  4.6%
0.1293 0.1147 11.3%
0.1354 0.1122 17.1%
0.0767 0.0770 -0.4%
0.1135 0.0968 14.7%
0.0524 0.0608 -16.0%
0.1279 0.1106 13.5%
==========
3.6820 3.0520 17.1% Total
```

Reviewers: twoh, Kader, danielcdh, wmi

Reviewed By: wmi

Subscribers: dblaikie, llvm-commits

Differential Revision: https://reviews.llvm.org/D56435

llvm-svn: 351211
This commit is contained in:
David Callahan 2019-01-15 17:45:54 +00:00
parent 9c53890833
commit dee001207e
1 changed files with 7 additions and 2 deletions
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9
llvm/lib/Transforms/IPO/SampleProfile.cpp
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@ -218,6 +218,7 @@ protected:
const FunctionSamples *findCalleeFunctionSamples(const Instruction &I) const;
std::vector<const FunctionSamples *>
findIndirectCallFunctionSamples(const Instruction &I, uint64_t &Sum) const;
mutable DenseMap<const DILocation *, const FunctionSamples *> DILocation2SampleMap;
const FunctionSamples *findFunctionSamples(const Instruction &I) const;
bool inlineCallInstruction(Instruction *I);
bool inlineHotFunctions(Function &F,
@ -719,12 +720,14 @@ SampleProfileLoader::findIndirectCallFunctionSamples(
/// \returns the FunctionSamples pointer to the inlined instance.
const FunctionSamples *
SampleProfileLoader::findFunctionSamples(const Instruction &Inst) const {
SmallVector<std::pair<LineLocation, StringRef>, 10> S;
const DILocation *DIL = Inst.getDebugLoc();
if (!DIL)
return Samples;
return Samples->findFunctionSamples(DIL);
auto it = DILocation2SampleMap.try_emplace(DIL,nullptr);
if (it.second)
it.first->second = Samples->findFunctionSamples(DIL);
return it.first->second;
}
bool SampleProfileLoader::inlineCallInstruction(Instruction *I) {
@ -1610,6 +1613,8 @@ bool SampleProfileLoaderLegacyPass::runOnModule(Module &M) {
}
bool SampleProfileLoader::runOnFunction(Function &F, ModuleAnalysisManager *AM) {
DILocation2SampleMap.clear();
// By default the entry count is initialized to -1, which will be treated
// conservatively by getEntryCount as the same as unknown (None). This is
// to avoid newly added code to be treated as cold. If we have samples