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P0811R3_midpoint_lerp: Avoid flaky ARM64/ARM64EC failures#6266
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StephanTLavavej merged 1 commit intoApr 29, 2026
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Pull request overview
This PR updates the P0811R3_midpoint_lerp test to avoid flaky ARM64/ARM64EC failures by centralizing the existing GH-5685 workaround inside check_feexcept(), so all floating-point exception checks become no-ops on those targets.
Changes:
- Updated
check_feexcept()to always succeed on_M_ARM64/_M_ARM64EC(TRANSITION, GH-5685). - Removed local ARM64/ARM64EC
#ifguards aroundcheck_feexcept()assertions (now handled uniformly by the helper).
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zacklj89
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Apr 29, 2026
BillyONeal
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This approval is contingent on a bug being filed with the compiler folks.
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This extends the workaround for #5685, originally introduced by #5687, to cover all occurrences of
check_feexcept().We've been seeing flaky ARM64/ARM64EC failures, both internally and externally, always of the form
lerp(1, 2, 2) == 3; expected 3. This indicates that the value bits are correct, but something's wrong with the floating-point exception state. This only started happening recently, without having messed withlerp(), so I speculate that something in the compiler changed.