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//===-- ParallelSnippetGenerator.h ------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
///
/// \file
/// A SnippetGenerator implementation to create parallel instruction snippets.
///
//===----------------------------------------------------------------------===//
#ifndef LLVM_TOOLS_LLVM_EXEGESIS_PARALLELSNIPPETGENERATOR_H
#define LLVM_TOOLS_LLVM_EXEGESIS_PARALLELSNIPPETGENERATOR_H
#include "SnippetGenerator.h"
namespace llvm {
namespace exegesis {
class ParallelSnippetGenerator : public SnippetGenerator {
public:
using SnippetGenerator::SnippetGenerator;
~ParallelSnippetGenerator() override;
Expected<std::vector<CodeTemplate>>
generateCodeTemplates(InstructionTemplate Variant,
const BitVector &ForbiddenRegisters) const override;
static constexpr const size_t kMinNumDifferentAddresses = 6;
private:
// 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<InstructionTemplate> &SnippetTemplate) const;
};
} // namespace exegesis
} // namespace llvm
#endif // LLVM_TOOLS_LLVM_EXEGESIS_PARALLELSNIPPETGENERATOR_H
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