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 | |