https://sourceware.org/bugzilla/show_bug.cgi?id=25550
--- Comment #6 from H.J. Lu <hjl.tools at gmail dot com> --- (In reply to Jan Beulich from comment #5) > (In reply to H.J. Lu from comment #4) > > (In reply to Jan Beulich from comment #3) > > > (In reply to H.J. Lu from comment #2) > > > > Is SSE2 a prerequisite for AVX? > > > > > > This can be viewed either way, I guess. The history of the ISA extensions > > > suggests it is. But functionally nothing except the XMM registers have any > > > overlap, I think. > > > > Why is AVX a prerequisite for AVX512? > > The correlation is largely the same as the one between SSE* and AVX. I agree with you on both counts. I think treating MMX, SSE, AVX and AVX512 as separate ISA families gives assembler the most flexibility. Of course, we need to document whatever behavior we decide. > > > > For view point of assembly codes, enable MMX register without MMX ISA > > > > makes no sense. For example, emms is needed for proper MMX usage. > > > > > > Not necessarily, one can certainly get away without (using 4 FFREEP in a > > > row). > > > > What purpose does it serve? > > Well, I don't expect anyone would actively want to use it this way. I think it is better to allow MMX register only if MMX ISA is enabled. -- You are receiving this mail because: You are on the CC list for the bug.
