Re:When O3 is 2x slower than O2
by sgerenser on Tuesday November 04, 2025 @01:24PM
(#45814212)
"Haswell or newer" is a bit misleading here, because there were low-end Celerons and Pentiums shipped for years after the release of Haswell that lacked AVX2 and wouldn't be able to run software compiled for -march=haswell.
I have a box that old that can run image diffusion models (I upgraded the GPU during covid.)
My point being that compiler authors do worry about “obsolete” targets because they’re widely used for compatibility reasons.