llvm-project/llvm/tools/llvm-exegesis/lib/Uops.h

81 lines
2.6 KiB
C++

//===-- Uops.h --------------------------------------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
///
/// \file
/// A BenchmarkRunner implementation to measure uop decomposition.
///
//===----------------------------------------------------------------------===//
#ifndef LLVM_TOOLS_LLVM_EXEGESIS_UOPS_H
#define LLVM_TOOLS_LLVM_EXEGESIS_UOPS_H
#include "BenchmarkRunner.h"
#include "SnippetGenerator.h"
namespace exegesis {
class UopsSnippetGenerator : public SnippetGenerator {
public:
UopsSnippetGenerator(const LLVMState &State) : SnippetGenerator(State) {}
~UopsSnippetGenerator() override;
llvm::Expected<CodeTemplate>
generateCodeTemplate(unsigned Opcode) const override;
static constexpr const size_t kMinNumDifferentAddresses = 6;
private:
llvm::Error isInfeasible(const llvm::MCInstrDesc &MCInstrDesc) const;
// Instantiates memory operands within a snippet.
// To make computations as parallel as possible, we generate independant
// memory locations for instructions that load and store. If there are less
// than kMinNumDifferentAddresses in the original snippet, we duplicate
// instructions until there are this number of instructions.
// For example, assuming kMinNumDifferentAddresses=5 and
// getMaxMemoryAccessSize()=64, if the original snippet is:
// mov eax, [memory]
// we might generate:
// mov eax, [rdi]
// mov eax, [rdi + 64]
// mov eax, [rdi + 128]
// mov eax, [rdi + 192]
// mov eax, [rdi + 256]
// If the original snippet is:
// mov eax, [memory]
// add eax, [memory]
// we might generate:
// mov eax, [rdi]
// add eax, [rdi + 64]
// mov eax, [rdi + 128]
// add eax, [rdi + 192]
// mov eax, [rdi + 256]
void
instantiateMemoryOperands(unsigned ScratchSpaceReg,
std::vector<InstructionBuilder> &Snippet) const;
};
class UopsBenchmarkRunner : public BenchmarkRunner {
public:
UopsBenchmarkRunner(const LLVMState &State)
: BenchmarkRunner(State, InstructionBenchmark::Uops) {}
~UopsBenchmarkRunner() override;
static constexpr const size_t kMinNumDifferentAddresses = 6;
private:
std::vector<BenchmarkMeasure>
runMeasurements(const ExecutableFunction &EF, ScratchSpace &Scratch,
const unsigned NumRepetitions) const override;
};
} // namespace exegesis
#endif // LLVM_TOOLS_LLVM_EXEGESIS_UOPS_H