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      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_SCALAR_INSTSIMPLIFYPASS_H
     15 #define LLVM_TRANSFORMS_SCALAR_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 } // end namespace llvm
     40 
     41 #endif // LLVM_TRANSFORMS_SCALAR_INSTSIMPLIFYPASS_H
     42