Prevent some invalid associativity in to_float implementation for avx…#1265
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serge-sans-paille merged 1 commit intomasterfrom Feb 27, 2026
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Prevent some invalid associativity in to_float implementation for avx…#1265serge-sans-paille merged 1 commit intomasterfrom
serge-sans-paille merged 1 commit intomasterfrom
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With -ffast-math (-fassociative-math), the compiler may reassociate (xH-C)+xL into xH+(xL-C). Since xL<<C this causes catastrophic cancellation, zeroing the result. Add an asm register barrier between the sub and add to prevent reassociation. The barrier forces the intermediate into a register without emitting any instructions. Fixes #1264
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@DiamonDinoia I've cherry-picked your patch, removed the redundant guard and pushed it here |
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Sure, it looks good! |
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…2 under -ffast-math
Fix #1264