1 //===-- PreISelIntrinsicLowering.cpp - Pre-ISel intrinsic lowering pass ---===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This pass implements IR lowering for the llvm.load.relative intrinsic.
12 //===----------------------------------------------------------------------===//
14 #include "llvm/CodeGen/PreISelIntrinsicLowering.h"
15 #include "llvm/CodeGen/Passes.h"
16 #include "llvm/IR/Function.h"
17 #include "llvm/IR/IRBuilder.h"
18 #include "llvm/IR/Instructions.h"
19 #include "llvm/IR/Intrinsics.h"
20 #include "llvm/IR/Module.h"
21 #include "llvm/Pass.h"
27 bool lowerLoadRelative(Function &F) {
32 Type *Int32Ty = Type::getInt32Ty(F.getContext());
33 Type *Int32PtrTy = Int32Ty->getPointerTo();
34 Type *Int8Ty = Type::getInt8Ty(F.getContext());
36 for (auto I = F.use_begin(), E = F.use_end(); I != E;) {
37 auto CI = dyn_cast<CallInst>(I->getUser());
39 if (!CI || CI->getCalledValue() != &F)
44 B.CreateGEP(Int8Ty, CI->getArgOperand(0), CI->getArgOperand(1));
45 Value *OffsetPtrI32 = B.CreateBitCast(OffsetPtr, Int32PtrTy);
46 Value *OffsetI32 = B.CreateAlignedLoad(OffsetPtrI32, 4);
48 Value *ResultPtr = B.CreateGEP(Int8Ty, CI->getArgOperand(0), OffsetI32);
50 CI->replaceAllUsesWith(ResultPtr);
51 CI->eraseFromParent();
58 bool lowerIntrinsics(Module &M) {
60 for (Function &F : M) {
61 if (F.getName().startswith("llvm.load.relative."))
62 Changed |= lowerLoadRelative(F);
67 class PreISelIntrinsicLoweringLegacyPass : public ModulePass {
70 PreISelIntrinsicLoweringLegacyPass() : ModulePass(ID) {}
72 bool runOnModule(Module &M) { return lowerIntrinsics(M); }
75 char PreISelIntrinsicLoweringLegacyPass::ID;
78 INITIALIZE_PASS(PreISelIntrinsicLoweringLegacyPass,
79 "pre-isel-intrinsic-lowering", "Pre-ISel Intrinsic Lowering",
83 ModulePass *createPreISelIntrinsicLoweringPass() {
84 return new PreISelIntrinsicLoweringLegacyPass;
87 PreservedAnalyses PreISelIntrinsicLoweringPass::run(Module &M,
88 ModuleAnalysisManager &AM) {
89 if (!lowerIntrinsics(M))
90 return PreservedAnalyses::all();
92 return PreservedAnalyses::none();
94 } // End llvm namespace