dd094b2647
This was much more difficult than I anticipated. The pass is not in a good state, with poor test coverage. The legacy PM does seem to be relying on maintaining the map state between different SCCs, which seems bad. The pass is going out of its way to avoid putting the attributes it introduces onto non-callee functions. If it just added them, we could use them directly instead of relying on the map, I would think. The NewPM path uses a ModulePass; I'm not sure if we should be using CGSCC here but there seems to be some missing infrastructure to support backend defined ones.
77 lines
2.3 KiB
C++
77 lines
2.3 KiB
C++
//===- AMDGPUPerfHintAnalysis.h ---- analysis of memory traffic -*- 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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/// \file
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/// \brief Analyzes if a function potentially memory bound and if a kernel
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/// kernel may benefit from limiting number of waves to reduce cache thrashing.
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///
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_LIB_TARGET_AMDGPU_AMDGPUPERFHINTANALYSIS_H
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#define LLVM_LIB_TARGET_AMDGPU_AMDGPUPERFHINTANALYSIS_H
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#include "llvm/IR/PassManager.h"
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#include "llvm/IR/ValueMap.h"
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#include "llvm/Analysis/CGSCCPassManager.h"
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#include "llvm/Analysis/LazyCallGraph.h"
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namespace llvm {
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class AMDGPUPerfHintAnalysis;
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class CallGraphSCC;
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class GCNTargetMachine;
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class LazyCallGraph;
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class AMDGPUPerfHintAnalysis {
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public:
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struct FuncInfo {
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unsigned MemInstCost;
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unsigned InstCost;
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unsigned IAMInstCost; // Indirect access memory instruction count
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unsigned LSMInstCost; // Large stride memory instruction count
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bool HasDenseGlobalMemAcc; // Set if at least 1 basic block has relatively
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// high global memory access
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FuncInfo()
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: MemInstCost(0), InstCost(0), IAMInstCost(0), LSMInstCost(0),
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HasDenseGlobalMemAcc(false) {}
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};
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typedef ValueMap<const Function *, FuncInfo> FuncInfoMap;
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private:
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FuncInfoMap FIM;
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public:
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AMDGPUPerfHintAnalysis() {}
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// OldPM
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bool runOnSCC(const GCNTargetMachine &TM, CallGraphSCC &SCC);
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// NewPM
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bool run(const GCNTargetMachine &TM, LazyCallGraph &CG);
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bool isMemoryBound(const Function *F) const;
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bool needsWaveLimiter(const Function *F) const;
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};
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struct AMDGPUPerfHintAnalysisPass
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: public PassInfoMixin<AMDGPUPerfHintAnalysisPass> {
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const GCNTargetMachine &TM;
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std::unique_ptr<AMDGPUPerfHintAnalysis> Impl;
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AMDGPUPerfHintAnalysisPass(const GCNTargetMachine &TM)
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: TM(TM), Impl(std::make_unique<AMDGPUPerfHintAnalysis>()) {}
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PreservedAnalyses run(Module &M, ModuleAnalysisManager &AM);
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};
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} // namespace llvm
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#endif // LLVM_LIB_TARGET_AMDGPU_AMDGPUPERFHINTANALYSIS_H
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