llvm/lib/Transforms/IPO/InlineSimple.cpp
Easwaran Raman adca57541a Improve PGO support for the new inliner
This adds the following to the new PM based inliner in PGO mode:

* Use block frequency analysis to derive callsite's profile count and use
that to adjust thresholds of hot and cold callsites.

* Incrementally update the BFI of the caller after a callee gets inlined
into it. This incremental update is only within an invocation of the run
method - BFI is not preserved across calls to run.
Update the function entry count of the callee after inlining it into a
caller.

* I've tuned the thresholds for the hot and cold callsites using a hacked
up version of the old inliner that explicitly computes BFI on a set of
internal benchmarks and spec. Once the new PM based pipeline stabilizes
(IIRC Chandler mentioned there are known issues) I'll benchmark this
again and adjust the thresholds if required.
Inliner PGO support.

Differential revision: https://reviews.llvm.org/D28331

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@292666 91177308-0d34-0410-b5e6-96231b3b80d8
2017-01-20 22:44:04 +00:00

113 lines
3.7 KiB
C++

//===- InlineSimple.cpp - Code to perform simple function inlining --------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements bottom-up inlining of functions into callees.
//
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/AssumptionCache.h"
#include "llvm/Analysis/CallGraph.h"
#include "llvm/Analysis/InlineCost.h"
#include "llvm/Analysis/ProfileSummaryInfo.h"
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/IR/CallSite.h"
#include "llvm/IR/CallingConv.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/IPO/Inliner.h"
using namespace llvm;
#define DEBUG_TYPE "inline"
namespace {
/// \brief Actual inliner pass implementation.
///
/// The common implementation of the inlining logic is shared between this
/// inliner pass and the always inliner pass. The two passes use different cost
/// analyses to determine when to inline.
class SimpleInliner : public LegacyInlinerBase {
InlineParams Params;
public:
SimpleInliner() : LegacyInlinerBase(ID), Params(llvm::getInlineParams()) {
initializeSimpleInlinerPass(*PassRegistry::getPassRegistry());
}
explicit SimpleInliner(InlineParams Params)
: LegacyInlinerBase(ID), Params(std::move(Params)) {
initializeSimpleInlinerPass(*PassRegistry::getPassRegistry());
}
static char ID; // Pass identification, replacement for typeid
InlineCost getInlineCost(CallSite CS) override {
Function *Callee = CS.getCalledFunction();
TargetTransformInfo &TTI = TTIWP->getTTI(*Callee);
std::function<AssumptionCache &(Function &)> GetAssumptionCache =
[&](Function &F) -> AssumptionCache & {
return ACT->getAssumptionCache(F);
};
return llvm::getInlineCost(CS, Params, TTI, GetAssumptionCache,
/*GetBFI=*/None, PSI);
}
bool runOnSCC(CallGraphSCC &SCC) override;
void getAnalysisUsage(AnalysisUsage &AU) const override;
private:
TargetTransformInfoWrapperPass *TTIWP;
};
} // end anonymous namespace
char SimpleInliner::ID = 0;
INITIALIZE_PASS_BEGIN(SimpleInliner, "inline", "Function Integration/Inlining",
false, false)
INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
INITIALIZE_PASS_DEPENDENCY(CallGraphWrapperPass)
INITIALIZE_PASS_DEPENDENCY(ProfileSummaryInfoWrapperPass)
INITIALIZE_PASS_DEPENDENCY(TargetTransformInfoWrapperPass)
INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
INITIALIZE_PASS_END(SimpleInliner, "inline", "Function Integration/Inlining",
false, false)
Pass *llvm::createFunctionInliningPass() { return new SimpleInliner(); }
Pass *llvm::createFunctionInliningPass(int Threshold) {
return new SimpleInliner(llvm::getInlineParams(Threshold));
}
Pass *llvm::createFunctionInliningPass(unsigned OptLevel,
unsigned SizeOptLevel) {
return new SimpleInliner(llvm::getInlineParams(OptLevel, SizeOptLevel));
}
Pass *llvm::createFunctionInliningPass(InlineParams &Params) {
return new SimpleInliner(Params);
}
bool SimpleInliner::runOnSCC(CallGraphSCC &SCC) {
TTIWP = &getAnalysis<TargetTransformInfoWrapperPass>();
return LegacyInlinerBase::runOnSCC(SCC);
}
void SimpleInliner::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<TargetTransformInfoWrapperPass>();
LegacyInlinerBase::getAnalysisUsage(AU);
}