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| 1 | +//===-- NVPTXLowerAlloca.cpp - Make alloca to use local memory =====--===// |
| 2 | +// |
| 3 | +// The LLVM Compiler Infrastructure |
| 4 | +// |
| 5 | +// This file is distributed under the University of Illinois Open Source |
| 6 | +// License. See LICENSE.TXT for details. |
| 7 | +// |
| 8 | +//===----------------------------------------------------------------------===// |
| 9 | +// |
| 10 | +// For all alloca instructions, and add a pair of cast to local address for |
| 11 | +// each of them. For example, |
| 12 | +// |
| 13 | +// %A = alloca i32 |
| 14 | +// store i32 0, i32* %A ; emits st.u32 |
| 15 | +// |
| 16 | +// will be transformed to |
| 17 | +// |
| 18 | +// %A = alloca i32 |
| 19 | +// %Local = addrspacecast i32* %A to i32 addrspace(5)* |
| 20 | +// %Generic = addrspacecast i32 addrspace(5)* %A to i32* |
| 21 | +// store i32 0, i32 addrspace(5)* %Generic ; emits st.local.u32 |
| 22 | +// |
| 23 | +// And we will rely on NVPTXFavorNonGenericAddrSpace to combine the last |
| 24 | +// two instructions. |
| 25 | +// |
| 26 | +//===----------------------------------------------------------------------===// |
| 27 | + |
| 28 | +#include "NVPTX.h" |
| 29 | +#include "NVPTXUtilities.h" |
| 30 | +#include "llvm/IR/Function.h" |
| 31 | +#include "llvm/IR/Instructions.h" |
| 32 | +#include "llvm/IR/IntrinsicInst.h" |
| 33 | +#include "llvm/IR/Module.h" |
| 34 | +#include "llvm/IR/Type.h" |
| 35 | +#include "llvm/Pass.h" |
| 36 | + |
| 37 | +using namespace llvm; |
| 38 | + |
| 39 | +namespace llvm { |
| 40 | +void initializeNVPTXLowerAllocaPass(PassRegistry &); |
| 41 | +} |
| 42 | + |
| 43 | +namespace { |
| 44 | +class NVPTXLowerAlloca : public BasicBlockPass { |
| 45 | + bool runOnBasicBlock(BasicBlock &BB) override; |
| 46 | + |
| 47 | +public: |
| 48 | + static char ID; // Pass identification, replacement for typeid |
| 49 | + NVPTXLowerAlloca() : BasicBlockPass(ID) {} |
| 50 | + const char *getPassName() const override { |
| 51 | + return "convert address space of alloca'ed memory to local"; |
| 52 | + } |
| 53 | +}; |
| 54 | +} // namespace |
| 55 | + |
| 56 | +char NVPTXLowerAlloca::ID = 1; |
| 57 | + |
| 58 | +INITIALIZE_PASS(NVPTXLowerAlloca, "nvptx-lower-alloca", |
| 59 | + "Lower Alloca", false, false) |
| 60 | + |
| 61 | +// ============================================================================= |
| 62 | +// Main function for this pass. |
| 63 | +// ============================================================================= |
| 64 | +bool NVPTXLowerAlloca::runOnBasicBlock(BasicBlock &BB) { |
| 65 | + bool Changed = false; |
| 66 | + for (auto &I : BB) { |
| 67 | + if (auto allocaInst = dyn_cast<AllocaInst>(&I)) { |
| 68 | + Changed = true; |
| 69 | + auto PTy = dyn_cast<PointerType>(allocaInst->getType()); |
| 70 | + auto ETy = PTy->getElementType(); |
| 71 | + auto LocalAddrTy = PointerType::get(ETy, ADDRESS_SPACE_LOCAL); |
| 72 | + auto NewASCToLocal = new AddrSpaceCastInst(allocaInst, LocalAddrTy, ""); |
| 73 | + auto GenericAddrTy = PointerType::get(ETy, ADDRESS_SPACE_GENERIC); |
| 74 | + auto NewASCToGeneric = new AddrSpaceCastInst(NewASCToLocal, |
| 75 | + GenericAddrTy, ""); |
| 76 | + NewASCToLocal->insertAfter(allocaInst); |
| 77 | + NewASCToGeneric->insertAfter(NewASCToLocal); |
| 78 | + for (Value::use_iterator UI = allocaInst->use_begin(), |
| 79 | + UE = allocaInst->use_end(); |
| 80 | + UI != UE; ) { |
| 81 | + // Check Load, Store, GEP, and BitCast Uses on alloca and make them |
| 82 | + // use the converted generic address, in order to expose non-generic |
| 83 | + // addrspacecast to NVPTXFavorNonGenericAddrSpace. For other types |
| 84 | + // of instructions this is unecessary and may introduce redudant |
| 85 | + // address cast. |
| 86 | + const auto &AllocaUse = *UI++; |
| 87 | + auto LI = dyn_cast<LoadInst>(AllocaUse.getUser()); |
| 88 | + if (LI && LI->getPointerOperand() == allocaInst && !LI->isVolatile()) { |
| 89 | + LI->setOperand(LI->getPointerOperandIndex(), NewASCToGeneric); |
| 90 | + continue; |
| 91 | + } |
| 92 | + auto SI = dyn_cast<StoreInst>(AllocaUse.getUser()); |
| 93 | + if (SI && SI->getPointerOperand() == allocaInst && !SI->isVolatile()) { |
| 94 | + SI->setOperand(SI->getPointerOperandIndex(), NewASCToGeneric); |
| 95 | + continue; |
| 96 | + } |
| 97 | + auto GI = dyn_cast<GetElementPtrInst>(AllocaUse.getUser()); |
| 98 | + if (GI && GI->getPointerOperand() == allocaInst) { |
| 99 | + GI->setOperand(GI->getPointerOperandIndex(), NewASCToGeneric); |
| 100 | + continue; |
| 101 | + } |
| 102 | + auto BI = dyn_cast<BitCastInst>(AllocaUse.getUser()); |
| 103 | + if (BI && BI->getOperand(0) == allocaInst) { |
| 104 | + BI->setOperand(0, NewASCToGeneric); |
| 105 | + continue; |
| 106 | + } |
| 107 | + } |
| 108 | + } |
| 109 | + } |
| 110 | + return Changed; |
| 111 | +} |
| 112 | + |
| 113 | +BasicBlockPass *llvm::createNVPTXLowerAllocaPass() { |
| 114 | + return new NVPTXLowerAlloca(); |
| 115 | +} |
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