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 /// Run instruction simplification across each instruction in the function.
22 ///
23 /// Instruction simplification has useful constraints in some contexts:
24 /// - It will never introduce *new* instructions.
25 /// - There is no need to iterate to a fixed point.
26 ///
27 /// Many passes use instruction simplification as a library facility, but it may
28 /// also be useful (in tests and other contexts) to have access to this very
29 /// restricted transform at a pass granularity. However, for a much more
30 /// powerful and comprehensive peephole optimization engine, see the
31 /// `instcombine` pass instead.
32 class InstSimplifyPass : public PassInfoMixin<InstSimplifyPass> {
33 public:
34   PreservedAnalyses run(Function &F, FunctionAnalysisManager &AM);
35 };
36 
37 } // end namespace llvm
38 
39 #endif // LLVM_TRANSFORMS_SCALAR_INSTSIMPLIFYPASS_H
40