1 //===- InstCombine.h - InstCombine pass -------------------------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 /// \file 9 /// 10 /// This file provides the primary interface to the instcombine pass. This pass 11 /// is suitable for use in the new pass manager. For a pass that works with the 12 /// legacy pass manager, use \c createInstructionCombiningPass(). 13 /// 14 //===----------------------------------------------------------------------===// 15 16 #ifndef LLVM_TRANSFORMS_INSTCOMBINE_INSTCOMBINE_H 17 #define LLVM_TRANSFORMS_INSTCOMBINE_INSTCOMBINE_H 18 19 #include "llvm/IR/Function.h" 20 #include "llvm/IR/PassManager.h" 21 #include "llvm/Pass.h" 22 23 #define DEBUG_TYPE "instcombine" 24 #include "llvm/Transforms/Utils/InstructionWorklist.h" 25 26 namespace llvm { 27 28 static constexpr unsigned InstCombineDefaultMaxIterations = 1; 29 30 struct InstCombineOptions { 31 bool UseLoopInfo = false; 32 // Verify that a fix point has been reached after MaxIterations. 33 bool VerifyFixpoint = false; 34 unsigned MaxIterations = InstCombineDefaultMaxIterations; 35 36 InstCombineOptions() = default; 37 38 InstCombineOptions &setUseLoopInfo(bool Value) { 39 UseLoopInfo = Value; 40 return *this; 41 } 42 43 InstCombineOptions &setVerifyFixpoint(bool Value) { 44 VerifyFixpoint = Value; 45 return *this; 46 } 47 48 InstCombineOptions &setMaxIterations(unsigned Value) { 49 MaxIterations = Value; 50 return *this; 51 } 52 }; 53 54 class InstCombinePass : public PassInfoMixin<InstCombinePass> { 55 private: 56 InstructionWorklist Worklist; 57 InstCombineOptions Options; 58 59 public: 60 explicit InstCombinePass(InstCombineOptions Opts = {}); 61 void printPipeline(raw_ostream &OS, 62 function_ref<StringRef(StringRef)> MapClassName2PassName); 63 64 PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM); 65 }; 66 67 /// The legacy pass manager's instcombine pass. 68 /// 69 /// This is a basic whole-function wrapper around the instcombine utility. It 70 /// will try to combine all instructions in the function. 71 class InstructionCombiningPass : public FunctionPass { 72 InstructionWorklist Worklist; 73 74 public: 75 static char ID; // Pass identification, replacement for typeid 76 77 explicit InstructionCombiningPass(); 78 79 void getAnalysisUsage(AnalysisUsage &AU) const override; 80 bool runOnFunction(Function &F) override; 81 }; 82 83 //===----------------------------------------------------------------------===// 84 // 85 // InstructionCombining - Combine instructions to form fewer, simple 86 // instructions. This pass does not modify the CFG, and has a tendency to make 87 // instructions dead, so a subsequent DCE pass is useful. 88 // 89 // This pass combines things like: 90 // %Y = add int 1, %X 91 // %Z = add int 1, %Y 92 // into: 93 // %Z = add int 2, %X 94 // 95 FunctionPass *createInstructionCombiningPass(); 96 } 97 98 #undef DEBUG_TYPE 99 100 #endif 101