1 //===- InstSimplifyPass.h ---------------------------------------*- 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 /// Defines passes for running instruction simplification across chunks of IR. 11 /// 12 //===----------------------------------------------------------------------===// 13 14 #ifndef LLVM_TRANSFORMS_UTILS_INSTSIMPLIFYPASS_H 15 #define LLVM_TRANSFORMS_UTILS_INSTSIMPLIFYPASS_H 16 17 #include "llvm/IR/PassManager.h" 18 19 namespace llvm { 20 21 class FunctionPass; 22 23 /// Run instruction simplification across each instruction in the function. 24 /// 25 /// Instruction simplification has useful constraints in some contexts: 26 /// - It will never introduce *new* instructions. 27 /// - There is no need to iterate to a fixed point. 28 /// 29 /// Many passes use instruction simplification as a library facility, but it may 30 /// also be useful (in tests and other contexts) to have access to this very 31 /// restricted transform at a pass granularity. However, for a much more 32 /// powerful and comprehensive peephole optimization engine, see the 33 /// `instcombine` pass instead. 34 class InstSimplifyPass : public PassInfoMixin<InstSimplifyPass> { 35 public: 36 PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM); 37 }; 38 39 /// Create a legacy pass that does instruction simplification on each 40 /// instruction in a function. 41 FunctionPass *createInstSimplifyLegacyPass(); 42 43 } // end namespace llvm 44 45 #endif // LLVM_TRANSFORMS_UTILS_INSTSIMPLIFYPASS_H 46