llvm-6502/lib/Transforms/IPO/InlineAlways.cpp
Andrew Trick b2ab2fa524 Inlining and unrolling heuristics should be aware of free truncs.
We want heuristics to be based on accurate data, but more importantly
we don't want llvm to behave randomly. A benign trunc inserted by an
upstream pass should not cause a wild swings in optimization
level. See PR11034. It's a general problem with threshold-based
heuristics, but we can make it less bad.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@140919 91177308-0d34-0410-b5e6-96231b3b80d8
2011-10-01 01:39:05 +00:00

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2.9 KiB
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//===- InlineAlways.cpp - Code to inline always_inline functions ----------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements a custom inliner that handles only functions that
// are marked as "always inline".
//
//===----------------------------------------------------------------------===//
#define DEBUG_TYPE "inline"
#include "llvm/CallingConv.h"
#include "llvm/Instructions.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/Module.h"
#include "llvm/Type.h"
#include "llvm/Analysis/CallGraph.h"
#include "llvm/Analysis/InlineCost.h"
#include "llvm/Support/CallSite.h"
#include "llvm/Transforms/IPO.h"
#include "llvm/Transforms/IPO/InlinerPass.h"
#include "llvm/Target/TargetData.h"
#include "llvm/ADT/SmallPtrSet.h"
using namespace llvm;
namespace {
// AlwaysInliner only inlines functions that are mark as "always inline".
class AlwaysInliner : public Inliner {
// Functions that are never inlined
SmallPtrSet<const Function*, 16> NeverInline;
InlineCostAnalyzer CA;
public:
// Use extremely low threshold.
AlwaysInliner() : Inliner(ID, -2000000000) {
initializeAlwaysInlinerPass(*PassRegistry::getPassRegistry());
}
static char ID; // Pass identification, replacement for typeid
InlineCost getInlineCost(CallSite CS) {
return CA.getInlineCost(CS, NeverInline);
}
float getInlineFudgeFactor(CallSite CS) {
return CA.getInlineFudgeFactor(CS);
}
void resetCachedCostInfo(Function *Caller) {
CA.resetCachedCostInfo(Caller);
}
void growCachedCostInfo(Function* Caller, Function* Callee) {
CA.growCachedCostInfo(Caller, Callee);
}
virtual bool doFinalization(CallGraph &CG) {
return removeDeadFunctions(CG, &NeverInline);
}
virtual bool doInitialization(CallGraph &CG);
void releaseMemory() {
CA.clear();
}
};
}
char AlwaysInliner::ID = 0;
INITIALIZE_PASS_BEGIN(AlwaysInliner, "always-inline",
"Inliner for always_inline functions", false, false)
INITIALIZE_AG_DEPENDENCY(CallGraph)
INITIALIZE_PASS_END(AlwaysInliner, "always-inline",
"Inliner for always_inline functions", false, false)
Pass *llvm::createAlwaysInlinerPass() { return new AlwaysInliner(); }
// doInitialization - Initializes the vector of functions that have not
// been annotated with the "always inline" attribute.
bool AlwaysInliner::doInitialization(CallGraph &CG) {
CA.setTargetData(getAnalysisIfAvailable<TargetData>());
Module &M = CG.getModule();
for (Module::iterator I = M.begin(), E = M.end();
I != E; ++I)
if (!I->isDeclaration() && !I->hasFnAttr(Attribute::AlwaysInline))
NeverInline.insert(I);
return false;
}