1 //===- HexagonRemoveExtendArgs.cpp - Remove unnecessary argument sign extends // 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 // Pass that removes sign extends for function parameters. These parameters 11 // are already sign extended by the caller per Hexagon's ABI 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "Hexagon.h" 16 #include "HexagonTargetMachine.h" 17 #include "llvm/CodeGen/MachineFunctionAnalysis.h" 18 #include "llvm/IR/Function.h" 19 #include "llvm/IR/Instructions.h" 20 #include "llvm/Pass.h" 21 #include "llvm/Transforms/Scalar.h" 22 23 using namespace llvm; 24 namespace { 25 struct HexagonRemoveExtendArgs : public FunctionPass { 26 public: 27 static char ID; 28 HexagonRemoveExtendArgs() : FunctionPass(ID) {} 29 virtual bool runOnFunction(Function &F); 30 31 const char *getPassName() const { 32 return "Remove sign extends"; 33 } 34 35 virtual void getAnalysisUsage(AnalysisUsage &AU) const { 36 AU.addRequired<MachineFunctionAnalysis>(); 37 AU.addPreserved<MachineFunctionAnalysis>(); 38 FunctionPass::getAnalysisUsage(AU); 39 } 40 }; 41 } 42 43 char HexagonRemoveExtendArgs::ID = 0; 44 RegisterPass<HexagonRemoveExtendArgs> X("reargs", 45 "Remove Sign and Zero Extends for Args" 46 ); 47 48 49 50 bool HexagonRemoveExtendArgs::runOnFunction(Function &F) { 51 unsigned Idx = 1; 52 for (Function::arg_iterator AI = F.arg_begin(), AE = F.arg_end(); AI != AE; 53 ++AI, ++Idx) { 54 if (F.getAttributes().hasAttribute(Idx, Attribute::SExt)) { 55 Argument* Arg = AI; 56 if (!isa<PointerType>(Arg->getType())) { 57 for (Instruction::use_iterator UI = Arg->use_begin(); 58 UI != Arg->use_end();) { 59 if (isa<SExtInst>(*UI)) { 60 Instruction* Use = cast<Instruction>(*UI); 61 SExtInst* SI = new SExtInst(Arg, Use->getType()); 62 assert (EVT::getEVT(SI->getType()) == 63 (EVT::getEVT(Use->getType()))); 64 ++UI; 65 Use->replaceAllUsesWith(SI); 66 Instruction* First = F.getEntryBlock().begin(); 67 SI->insertBefore(First); 68 Use->eraseFromParent(); 69 } else { 70 ++UI; 71 } 72 } 73 } 74 } 75 } 76 return true; 77 } 78 79 80 81 FunctionPass *llvm::createHexagonRemoveExtendOps(HexagonTargetMachine &TM) { 82 return new HexagonRemoveExtendArgs(); 83 } 84
