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to reflect the new license. We understand that people may be surprised that we're moving the header entirely to discuss the new license. We checked this carefully with the Foundation's lawyer and we believe this is the correct approach. Essentially, all code in the project is now made available by the LLVM project under our new license, so you will see that the license headers include that license only. Some of our contributors have contributed code under our old license, and accordingly, we have retained a copy of our old license notice in the top-level files in each project and repository. llvm-svn: 351636
69 lines
2.4 KiB
C++
69 lines
2.4 KiB
C++
//===- llvm/Analysis/LegacyDivergenceAnalysis.h - KernelDivergence Analysis -*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// The kernel divergence analysis is an LLVM pass which can be used to find out
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// if a branch instruction in a GPU program (kernel) is divergent or not. It can help
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// branch optimizations such as jump threading and loop unswitching to make
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// better decisions.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_ANALYSIS_LEGACY_DIVERGENCE_ANALYSIS_H
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#define LLVM_ANALYSIS_LEGACY_DIVERGENCE_ANALYSIS_H
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#include "llvm/ADT/DenseSet.h"
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#include "llvm/IR/Function.h"
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#include "llvm/Pass.h"
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#include "llvm/Analysis/DivergenceAnalysis.h"
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namespace llvm {
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class Value;
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class GPUDivergenceAnalysis;
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class LegacyDivergenceAnalysis : public FunctionPass {
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public:
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static char ID;
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LegacyDivergenceAnalysis() : FunctionPass(ID) {
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initializeLegacyDivergenceAnalysisPass(*PassRegistry::getPassRegistry());
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}
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void getAnalysisUsage(AnalysisUsage &AU) const override;
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bool runOnFunction(Function &F) override;
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// Print all divergent branches in the function.
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void print(raw_ostream &OS, const Module *) const override;
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// Returns true if V is divergent at its definition.
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//
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// Even if this function returns false, V may still be divergent when used
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// in a different basic block.
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bool isDivergent(const Value *V) const;
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// Returns true if V is uniform/non-divergent.
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//
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// Even if this function returns true, V may still be divergent when used
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// in a different basic block.
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bool isUniform(const Value *V) const { return !isDivergent(V); }
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// Keep the analysis results uptodate by removing an erased value.
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void removeValue(const Value *V) { DivergentValues.erase(V); }
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private:
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// Whether analysis should be performed by GPUDivergenceAnalysis.
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bool shouldUseGPUDivergenceAnalysis(const Function &F) const;
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// (optional) handle to new DivergenceAnalysis
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std::unique_ptr<GPUDivergenceAnalysis> gpuDA;
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// Stores all divergent values.
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DenseSet<const Value *> DivergentValues;
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};
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} // End llvm namespace
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#endif //LLVM_ANALYSIS_LEGACY_DIVERGENCE_ANALYSIS_H
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