llvm/lib/Transforms/IPO/InlineSimple.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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//===- 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.
//
//===----------------------------------------------------------------------===//
#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 {
class SimpleInliner : public Inliner {
// Functions that are never inlined
SmallPtrSet<const Function*, 16> NeverInline;
InlineCostAnalyzer CA;
public:
SimpleInliner() : Inliner(ID) {
initializeSimpleInlinerPass(*PassRegistry::getPassRegistry());
}
SimpleInliner(int Threshold) : Inliner(ID, Threshold) {
initializeSimpleInlinerPass(*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 doInitialization(CallGraph &CG);
void releaseMemory() {
CA.clear();
}
};
}
char SimpleInliner::ID = 0;
INITIALIZE_PASS_BEGIN(SimpleInliner, "inline",
"Function Integration/Inlining", false, false)
INITIALIZE_AG_DEPENDENCY(CallGraph)
INITIALIZE_PASS_END(SimpleInliner, "inline",
"Function Integration/Inlining", false, false)
Pass *llvm::createFunctionInliningPass() { return new SimpleInliner(); }
Pass *llvm::createFunctionInliningPass(int Threshold) {
return new SimpleInliner(Threshold);
}
// doInitialization - Initializes the vector of functions that have been
// annotated with the noinline attribute.
bool SimpleInliner::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::NoInline))
NeverInline.insert(I);
// Get llvm.noinline
GlobalVariable *GV = M.getNamedGlobal("llvm.noinline");
if (GV == 0)
return false;
// Don't crash on invalid code
if (!GV->hasDefinitiveInitializer())
return false;
const ConstantArray *InitList = dyn_cast<ConstantArray>(GV->getInitializer());
if (InitList == 0)
return false;
// Iterate over each element and add to the NeverInline set
for (unsigned i = 0, e = InitList->getNumOperands(); i != e; ++i) {
// Get Source
const Constant *Elt = InitList->getOperand(i);
if (const ConstantExpr *CE = dyn_cast<ConstantExpr>(Elt))
if (CE->getOpcode() == Instruction::BitCast)
Elt = CE->getOperand(0);
// Insert into set of functions to never inline
if (const Function *F = dyn_cast<Function>(Elt))
NeverInline.insert(F);
}
return false;
}