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b0c8c45423
Multiplying raw block frequency with an integer carries a high risk of overflow. - Add `BlockFrequency::mul` return an std::optional with the product or `nullopt` to indicate an overflow. - Fix two instances where overflow was likely.
48 lines
1.4 KiB
C++
48 lines
1.4 KiB
C++
//====--------------- lib/Support/BlockFrequency.cpp -----------*- 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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// This file implements Block Frequency class.
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//
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//===----------------------------------------------------------------------===//
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#include "llvm/Support/BlockFrequency.h"
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#include "llvm/Support/BranchProbability.h"
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#include "llvm/Support/MathExtras.h"
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using namespace llvm;
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BlockFrequency &BlockFrequency::operator*=(BranchProbability Prob) {
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Frequency = Prob.scale(Frequency);
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return *this;
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}
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BlockFrequency BlockFrequency::operator*(BranchProbability Prob) const {
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BlockFrequency Freq(Frequency);
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Freq *= Prob;
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return Freq;
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}
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BlockFrequency &BlockFrequency::operator/=(BranchProbability Prob) {
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Frequency = Prob.scaleByInverse(Frequency);
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return *this;
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}
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BlockFrequency BlockFrequency::operator/(BranchProbability Prob) const {
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BlockFrequency Freq(Frequency);
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Freq /= Prob;
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return Freq;
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}
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std::optional<BlockFrequency> BlockFrequency::mul(uint64_t Factor) const {
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bool Overflow;
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uint64_t ResultFrequency = SaturatingMultiply(Frequency, Factor, &Overflow);
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if (Overflow)
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return {};
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return BlockFrequency(ResultFrequency);
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}
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