llvm-6502/lib/Target/Hexagon/HexagonRemoveSZExtArgs.cpp

90 lines
2.7 KiB
C++

//===- HexagonRemoveExtendArgs.cpp - Remove unnecessary argument sign extends //
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// Pass that removes sign extends for function parameters. These parameters
// are already sign extended by the caller per Hexagon's ABI
//
//===----------------------------------------------------------------------===//
#include "Hexagon.h"
#include "HexagonTargetMachine.h"
#include "llvm/CodeGen/MachineFunctionAnalysis.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Instructions.h"
#include "llvm/Pass.h"
#include "llvm/Transforms/Scalar.h"
using namespace llvm;
namespace llvm {
void initializeHexagonRemoveExtendArgsPass(PassRegistry&);
}
namespace {
struct HexagonRemoveExtendArgs : public FunctionPass {
public:
static char ID;
HexagonRemoveExtendArgs() : FunctionPass(ID) {
initializeHexagonRemoveExtendArgsPass(*PassRegistry::getPassRegistry());
}
bool runOnFunction(Function &F) override;
const char *getPassName() const override {
return "Remove sign extends";
}
void getAnalysisUsage(AnalysisUsage &AU) const override {
AU.addRequired<MachineFunctionAnalysis>();
AU.addPreserved<MachineFunctionAnalysis>();
AU.addPreserved("stack-protector");
FunctionPass::getAnalysisUsage(AU);
}
};
}
char HexagonRemoveExtendArgs::ID = 0;
INITIALIZE_PASS(HexagonRemoveExtendArgs, "reargs",
"Remove Sign and Zero Extends for Args", false, false)
bool HexagonRemoveExtendArgs::runOnFunction(Function &F) {
unsigned Idx = 1;
for (Function::arg_iterator AI = F.arg_begin(), AE = F.arg_end(); AI != AE;
++AI, ++Idx) {
if (F.getAttributes().hasAttribute(Idx, Attribute::SExt)) {
Argument* Arg = AI;
if (!isa<PointerType>(Arg->getType())) {
for (auto UI = Arg->user_begin(); UI != Arg->user_end();) {
if (isa<SExtInst>(*UI)) {
Instruction* I = cast<Instruction>(*UI);
SExtInst* SI = new SExtInst(Arg, I->getType());
assert (EVT::getEVT(SI->getType()) ==
(EVT::getEVT(I->getType())));
++UI;
I->replaceAllUsesWith(SI);
Instruction* First = F.getEntryBlock().begin();
SI->insertBefore(First);
I->eraseFromParent();
} else {
++UI;
}
}
}
}
}
return true;
}
FunctionPass*
llvm::createHexagonRemoveExtendArgs(const HexagonTargetMachine &TM) {
return new HexagonRemoveExtendArgs();
}