https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119083
H.J. Lu <hjl.tools at gmail dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- Ever confirmed|0 |1 Status|UNCONFIRMED |NEW Last reconfirmed| |2025-03-03 --- Comment #4 from H.J. Lu <hjl.tools at gmail dot com> --- (In reply to Uroš Bizjak from comment #1) > SSE_FIRST_REG is in ic86_class_likely_spilled_p because it is a > single-member class. It is there because of SSE4 pcmpistrm patterns. > > %eax (and other single_class) registers are also listed in > CLASS_LIKELY_SPILLED_P, they are also (very) commonly used, and there were > no problems with that. So, why is %xmm0 different? I will try removing AX, BX, CX and DX from ix86_class_likely_spilled_p. I will keep DI and SI since they are fixed in the string instructions.