1 //===- ConstantMerge.h - Merge duplicate global constants -------*- 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 //
9 // This file defines the interface to a pass that merges duplicate global
10 // constants together into a single constant that is shared.  This is useful
11 // because some passes (ie TraceValues) insert a lot of string constants into
12 // the program, regardless of whether or not an existing string is available.
13 //
14 // Algorithm: ConstantMerge is designed to build up a map of available constants
15 // and eliminate duplicates when it is initialized.
16 //
17 //===----------------------------------------------------------------------===//
18 
19 #ifndef LLVM_TRANSFORMS_IPO_CONSTANTMERGE_H
20 #define LLVM_TRANSFORMS_IPO_CONSTANTMERGE_H
21 
22 #include "llvm/IR/PassManager.h"
23 
24 namespace llvm {
25 
26 class Module;
27 
28 /// A pass that merges duplicate global constants into a single constant.
29 class ConstantMergePass : public PassInfoMixin<ConstantMergePass> {
30 public:
31   PreservedAnalyses run(Module &M, ModuleAnalysisManager &);
32 };
33 
34 } // end namespace llvm
35 
36 #endif // LLVM_TRANSFORMS_IPO_CONSTANTMERGE_H
37