Matthias Klose, le jeu. 13 févr. 2025 12:35:51 +0100, a ecrit: > Mixing fp87 and SSE instructions leads to a performance penalty
When they are mixed within a function, sure. But between functions (and actually it's even about between libraries here, so even less often), I don't see why. So again, I don't see why bumping in rust (which will really fix things there) should imply bumping in the rest of the toolchain. Raising the *allowed* i386 baseline does not suddenly force the whole toolchain to actively try more to use more than it currently does. > (I don't have references to that, so people might want to > investigate). The references I can find only talk about within a function. > fp87 instructions also show some excess precision, so test cases and test > suites of packages might be affected by this change as well. Indeed. In the case of the rust toolchain, it's actually in the good direction: upstream tests do assume not using fp87. > Is this really worth doing that change, To avoid the fp87 unsoundness in rust that does produce bugs, yes. Samuel
