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/*
* (C) 2015 by Computer System Laboratory, IIS, Academia Sinica, Taiwan.
* See COPYRIGHT in top-level directory.
*/
#include "llvm/Transforms/Utils/Local.h"
#include "llvm-target.h"
#include "llvm-opc.h"
#include "llvm-pass.h"
#include "utils.h"
#define PASS_NAME "CombineZExtTrunc"
/*
* CombineZExtTrunc Pass
*/
class CombineZExtTrunc : public FunctionPass {
public:
static char ID;
explicit CombineZExtTrunc() : FunctionPass(ID) {}
bool runOnFunction(Function &F);
};
char CombineZExtTrunc::ID = 0;
INITIALIZE_PASS(CombineZExtTrunc, "combinezet",
"Combine ZExt followed by Trunc", false, false)
FunctionPass *llvm::createCombineZExtTrunc()
{
return new CombineZExtTrunc;
}
bool CombineZExtTrunc::runOnFunction(Function &F)
{
bool Changed = false;
IVec toErase;
SmallVector<Instruction*, 4> Worklist;
for (auto II = inst_begin(F), EE = inst_end(F); II != EE; II++) {
Instruction *I = &*II;
if (isa<TruncInst>(I))
Worklist.push_back(I);
}
for (auto I : Worklist) {
TruncInst *TI = cast<TruncInst>(I);
ZExtInst *ZI = dyn_cast<ZExtInst>(TI->getOperand(0));
if (!ZI)
continue;
Type *SrcTy = ZI->getOperand(0)->getType();
Type *DstTy = TI->getType();
if (SrcTy == DstTy) {
I->replaceAllUsesWith(ZI->getOperand(0));
if (TI->use_empty())
toErase.push_back(TI);
Changed = true;
}
}
if (toErase.size())
ProcessErase(toErase);
return Changed;
}
/*
* vim: ts=8 sts=4 sw=4 expandtab
*/
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