include/llvm/Transforms/Scalar/InstSimplifyPass.h

   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