http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54239
Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jakub at gcc dot gnu.org --- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-08-13 12:31:52 UTC --- Both in 4.7 (which is before the prfchw changes) and 4.8 with -m32 -m3dnow and -m32 -m3dnow -mno-sse I get prefetch + prefetchw insn, which looks ok to me. -mno-mmx I think disables 3dnow too, so you get no prefetch insns in that case (which is also fine). -mprfchw implies the SSE prefetches and PRFCHW CPUID 0x80000001 ecx bit 8 doesn't imply the prefetch insn, just prefetchw, so it is correct that with -m32 -mprfchw prefetchnta + prefetchw is generated. So, where exactly do you see a bug?