On 20/07/2022 14:36, Jan Beulich wrote: > On 20.07.2022 15:33, Andrew Cooper wrote: >> On 20/07/2022 14:30, Jan Beulich wrote: >>> Passing -mno-sse alone is not enough: The compiler may still find >>> (questionable) reasons to use MMX insns. In particular with gcc12 use >>> of MOVD+PUNPCKLDQ+MOVQ was observed in an apparent attempt to auto- >>> vectorize the storing of two adjacent zeroes, 32 bits each. >>> >>> Reported-by: ChrisD <[email protected]> >>> Signed-off-by: Jan Beulich <[email protected]> >> Acked-by: Andrew Cooper <[email protected]> > Thanks. > >> But while we're at it, what else might we have to clobber to stop >> nonsense like this? x87 and avx come to mind. > AVX is taking SSE as a prereq (with -mno-sse %xmm etc registers simply > are unavailable). And with -msoft-float I would very much hope we have > clearly indicated to the compiler that we want no x87 insns whatsoever.
Ok. Sounds plausible. ~Andrew
