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[BOLT][AArch64] Use minimal code alignment for cold functions #172598

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Merged
maksfb merged 1 commit into from
Dec 18, 2025
Merged

[BOLT][AArch64] Use minimal code alignment for cold functions #172598

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7 changes: 7 additions & 0 deletions bolt/lib/Passes/Aligner.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -77,6 +77,13 @@ static void alignCompact(BinaryFunction &Function,
size_t HotSize = 0;
size_t ColdSize = 0;

// On AArch64, larger cold code size may lead to more veneers and higher
// potential overhead for hot code. Minimize the cold code size.
if (!Function.hasProfile() && BC.isAArch64()) {
Function.setAlignment(Function.getMinAlignment());
return;
}

for (const BinaryBasicBlock &BB : Function)
if (BB.isSplit())
ColdSize += BC.computeCodeSize(BB.begin(), BB.end(), Emitter);
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