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[LibCallsShrinkWrap] Teach the pass how to preserve the dominator. 

llvm-svn: 301471
This commit is contained in:
Davide Italiano 2017-04-26 21:05:40 +00:00
parent 204103f3f4
commit 6abada8ab8
1 changed files with 25 additions and 7 deletions
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32
llvm/lib/Transforms/Utils/LibCallsShrinkWrap.cpp
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@ -33,6 +33,7 @@
#include "llvm/Analysis/TargetLibraryInfo.h"
#include "llvm/IR/CFG.h"
#include "llvm/IR/Constants.h"
#include "llvm/IR/Dominators.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/IRBuilder.h"
#include "llvm/IR/InstVisitor.h"
@ -82,7 +83,8 @@ INITIALIZE_PASS_END(LibCallsShrinkWrapLegacyPass, "libcalls-shrinkwrap",
namespace {
class LibCallsShrinkWrap : public InstVisitor<LibCallsShrinkWrap> {
public:
LibCallsShrinkWrap(const TargetLibraryInfo &TLI) : TLI(TLI), Changed(false){};
LibCallsShrinkWrap(const TargetLibraryInfo &TLI, DominatorTree *DT)
: TLI(TLI), DT(DT), Changed(false){};
bool isChanged() const { return Changed; }
void visitCallInst(CallInst &CI) { checkCandidate(CI); }
void perform() {
@ -134,6 +136,7 @@ private:
}
const TargetLibraryInfo &TLI;
DominatorTree *DT;
SmallVector<CallInst *, 16> WorkList;
bool Changed;
};
@ -502,11 +505,14 @@ void LibCallsShrinkWrap::shrinkWrapCI(CallInst *CI, Value *Cond) {
assert(Cond != nullptr && "hrinkWrapCI is not expecting an empty call inst");
MDNode *BranchWeights =
MDBuilder(CI->getContext()).createBranchWeights(1, 2000);
TerminatorInst *NewInst =
SplitBlockAndInsertIfThen(Cond, CI, false, BranchWeights);
SplitBlockAndInsertIfThen(Cond, CI, false, BranchWeights, DT);
BasicBlock *CallBB = NewInst->getParent();
CallBB->setName("cdce.call");
CallBB->getSingleSuccessor()->setName("cdce.end");
BasicBlock *SuccBB = CallBB->getSingleSuccessor();
assert(SuccBB && "The split block should have a single successor");
SuccBB->setName("cdce.end");
CI->removeFromParent();
CallBB->getInstList().insert(CallBB->getFirstInsertionPt(), CI);
DEBUG(dbgs() << "== Basic Block After ==");
@ -532,22 +538,32 @@ bool LibCallsShrinkWrap::perform(CallInst *CI) {
}
void LibCallsShrinkWrapLegacyPass::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addPreserved<DominatorTreeWrapperPass>();
AU.addPreserved<GlobalsAAWrapperPass>();
AU.addRequired<TargetLibraryInfoWrapperPass>();
}
static bool runImpl(Function &F, const TargetLibraryInfo &TLI) {
static bool runImpl(Function &F, const TargetLibraryInfo &TLI,
DominatorTree *DT) {
if (F.hasFnAttribute(Attribute::OptimizeForSize))
return false;
LibCallsShrinkWrap CCDCE(TLI);
LibCallsShrinkWrap CCDCE(TLI, DT);
CCDCE.visit(F);
CCDCE.perform();
// Verify the dominator after we've updated it locally.
#ifndef NDEBUG
if (DT)
DT->verifyDomTree();
#endif
return CCDCE.isChanged();
}
bool LibCallsShrinkWrapLegacyPass::runOnFunction(Function &F) {
auto &TLI = getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
return runImpl(F, TLI);
auto *DTWP = getAnalysisIfAvailable<DominatorTreeWrapperPass>();
auto *DT = DTWP ? &DTWP->getDomTree() : nullptr;
return runImpl(F, TLI, DT);
}
namespace llvm {
@ -561,11 +577,13 @@ FunctionPass *createLibCallsShrinkWrapPass() {
PreservedAnalyses LibCallsShrinkWrapPass::run(Function &F,
FunctionAnalysisManager &FAM) {
auto &TLI = FAM.getResult<TargetLibraryAnalysis>(F);
bool Changed = runImpl(F, TLI);
auto *DT = FAM.getCachedResult<DominatorTreeAnalysis>(F);
bool Changed = runImpl(F, TLI, DT);
if (!Changed)
return PreservedAnalyses::all();
auto PA = PreservedAnalyses();
PA.preserve<GlobalsAA>();
PA.preserve<DominatorTreeAnalysis>();
return PA;
}
}