forked from OSchip/llvm-project
99 lines
3.1 KiB
C++
99 lines
3.1 KiB
C++
//===------ RewriteByReferenceParameters.cpp --------------------*- C++ -*-===//
|
|
//
|
|
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
|
|
// See https://llvm.org/LICENSE.txt for license information.
|
|
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
//
|
|
// This pass introduces separate 'alloca' instructions for read-only
|
|
// by-reference function parameters to indicate that these paramters are
|
|
// read-only. After this transformation -mem2reg has more freedom to promote
|
|
// variables to registers, which allows SCEV to work in more cases.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#include "polly/LinkAllPasses.h"
|
|
#include "llvm/IR/Instruction.h"
|
|
#include "llvm/IR/Instructions.h"
|
|
#include "llvm/Pass.h"
|
|
|
|
#define DEBUG_TYPE "polly-rewrite-byref-params"
|
|
|
|
using namespace llvm;
|
|
|
|
namespace {
|
|
|
|
class RewriteByrefParams : public FunctionPass {
|
|
private:
|
|
RewriteByrefParams(const RewriteByrefParams &) = delete;
|
|
const RewriteByrefParams &operator=(const RewriteByrefParams &) = delete;
|
|
|
|
public:
|
|
static char ID;
|
|
explicit RewriteByrefParams() : FunctionPass(ID) {}
|
|
|
|
virtual void getAnalysisUsage(AnalysisUsage &AU) const override {}
|
|
|
|
void tryRewriteInstruction(Instruction &Inst) {
|
|
BasicBlock *Entry = &Inst.getParent()->getParent()->getEntryBlock();
|
|
|
|
auto *Call = dyn_cast<CallInst>(&Inst);
|
|
|
|
if (!Call)
|
|
return;
|
|
|
|
llvm::Function *F = Call->getCalledFunction();
|
|
|
|
if (!F)
|
|
return;
|
|
|
|
// We currently match for a very specific function. In case this proves
|
|
// useful, we can make this code dependent on readonly metadata.
|
|
if (!F->hasName() || F->getName() != "_gfortran_transfer_integer_write")
|
|
return;
|
|
|
|
auto *BitCast = dyn_cast<BitCastInst>(Call->getOperand(1));
|
|
|
|
if (!BitCast)
|
|
return;
|
|
|
|
auto *Alloca = dyn_cast<AllocaInst>(BitCast->getOperand(0));
|
|
|
|
if (!Alloca)
|
|
return;
|
|
|
|
std::string InstName = Alloca->getName();
|
|
|
|
auto NewAlloca =
|
|
new AllocaInst(Alloca->getType()->getElementType(), 0,
|
|
"polly_byref_alloca_" + InstName, &*Entry->begin());
|
|
|
|
auto *LoadedVal =
|
|
new LoadInst(Alloca, "polly_byref_load_" + InstName, &Inst);
|
|
|
|
new StoreInst(LoadedVal, NewAlloca, &Inst);
|
|
auto *NewBitCast = new BitCastInst(NewAlloca, BitCast->getType(),
|
|
"polly_byref_cast_" + InstName, &Inst);
|
|
Call->setOperand(1, NewBitCast);
|
|
}
|
|
|
|
virtual bool runOnFunction(Function &F) override {
|
|
for (BasicBlock &BB : F)
|
|
for (Instruction &Inst : BB)
|
|
tryRewriteInstruction(Inst);
|
|
|
|
return true;
|
|
}
|
|
};
|
|
|
|
char RewriteByrefParams::ID;
|
|
} // anonymous namespace
|
|
|
|
Pass *polly::createRewriteByrefParamsPass() { return new RewriteByrefParams(); }
|
|
|
|
INITIALIZE_PASS_BEGIN(RewriteByrefParams, "polly-rewrite-byref-params",
|
|
"Polly - Rewrite by reference parameters", false, false)
|
|
INITIALIZE_PASS_END(RewriteByrefParams, "polly-rewrite-byref-params",
|
|
"Polly - Rewrite by reference parameters", false, false)
|