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llvm-mirror/lib/Target/NVPTX/NVPTXLowerAlloca.cpp
Chandler Carruth ae65e281f3 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00

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4.2 KiB
C++

//===-- NVPTXLowerAlloca.cpp - Make alloca to use local memory =====--===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// For all alloca instructions, and add a pair of cast to local address for
// each of them. For example,
//
// %A = alloca i32
// store i32 0, i32* %A ; emits st.u32
//
// will be transformed to
//
// %A = alloca i32
// %Local = addrspacecast i32* %A to i32 addrspace(5)*
// %Generic = addrspacecast i32 addrspace(5)* %A to i32*
// store i32 0, i32 addrspace(5)* %Generic ; emits st.local.u32
//
// And we will rely on NVPTXInferAddressSpaces to combine the last two
// instructions.
//
//===----------------------------------------------------------------------===//
#include "NVPTX.h"
#include "NVPTXUtilities.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Module.h"
#include "llvm/IR/Type.h"
#include "llvm/Pass.h"
using namespace llvm;
namespace llvm {
void initializeNVPTXLowerAllocaPass(PassRegistry &);
}
namespace {
class NVPTXLowerAlloca : public BasicBlockPass {
bool runOnBasicBlock(BasicBlock &BB) override;
public:
static char ID; // Pass identification, replacement for typeid
NVPTXLowerAlloca() : BasicBlockPass(ID) {}
StringRef getPassName() const override {
return "convert address space of alloca'ed memory to local";
}
};
} // namespace
char NVPTXLowerAlloca::ID = 1;
INITIALIZE_PASS(NVPTXLowerAlloca, "nvptx-lower-alloca",
"Lower Alloca", false, false)
// =============================================================================
// Main function for this pass.
// =============================================================================
bool NVPTXLowerAlloca::runOnBasicBlock(BasicBlock &BB) {
if (skipBasicBlock(BB))
return false;
bool Changed = false;
for (auto &I : BB) {
if (auto allocaInst = dyn_cast<AllocaInst>(&I)) {
Changed = true;
auto PTy = dyn_cast<PointerType>(allocaInst->getType());
auto ETy = PTy->getElementType();
auto LocalAddrTy = PointerType::get(ETy, ADDRESS_SPACE_LOCAL);
auto NewASCToLocal = new AddrSpaceCastInst(allocaInst, LocalAddrTy, "");
auto GenericAddrTy = PointerType::get(ETy, ADDRESS_SPACE_GENERIC);
auto NewASCToGeneric = new AddrSpaceCastInst(NewASCToLocal,
GenericAddrTy, "");
NewASCToLocal->insertAfter(allocaInst);
NewASCToGeneric->insertAfter(NewASCToLocal);
for (Value::use_iterator UI = allocaInst->use_begin(),
UE = allocaInst->use_end();
UI != UE; ) {
// Check Load, Store, GEP, and BitCast Uses on alloca and make them
// use the converted generic address, in order to expose non-generic
// addrspacecast to NVPTXInferAddressSpaces. For other types
// of instructions this is unnecessary and may introduce redundant
// address cast.
const auto &AllocaUse = *UI++;
auto LI = dyn_cast<LoadInst>(AllocaUse.getUser());
if (LI && LI->getPointerOperand() == allocaInst && !LI->isVolatile()) {
LI->setOperand(LI->getPointerOperandIndex(), NewASCToGeneric);
continue;
}
auto SI = dyn_cast<StoreInst>(AllocaUse.getUser());
if (SI && SI->getPointerOperand() == allocaInst && !SI->isVolatile()) {
SI->setOperand(SI->getPointerOperandIndex(), NewASCToGeneric);
continue;
}
auto GI = dyn_cast<GetElementPtrInst>(AllocaUse.getUser());
if (GI && GI->getPointerOperand() == allocaInst) {
GI->setOperand(GI->getPointerOperandIndex(), NewASCToGeneric);
continue;
}
auto BI = dyn_cast<BitCastInst>(AllocaUse.getUser());
if (BI && BI->getOperand(0) == allocaInst) {
BI->setOperand(0, NewASCToGeneric);
continue;
}
}
}
}
return Changed;
}
BasicBlockPass *llvm::createNVPTXLowerAllocaPass() {
return new NVPTXLowerAlloca();
}