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