https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110452
--- Comment #1 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Richard Biener <rgue...@gcc.gnu.org>: https://gcc.gnu.org/g:6d2eddf456f2d6494cac490c4aa3e7d089926098 commit r14-2183-g6d2eddf456f2d6494cac490c4aa3e7d089926098 Author: Richard Biener <rguent...@suse.de> Date: Wed Jun 28 14:05:55 2023 +0200 middle-end/110452 - bad code generation with AVX512 mask splat The following adds an alternate way of expanding a uniform mask vector constructor like _55 = _2 ? -1 : 0; vect_cst__56 = {_55, _55, _55, _55, _55, _55, _55, _55}; when the mask mode is a scalar int mode like for AVX512 or GCN. Instead of piecewise building the result via shifts and ors we can take advantage of uniformity and signedness of the component and simply sign-extend to the result. Instead of cmpl $3, %edi sete %cl movl %ecx, %esi leal (%rsi,%rsi), %eax leal 0(,%rsi,4), %r9d leal 0(,%rsi,8), %r8d orl %esi, %eax orl %r9d, %eax movl %ecx, %r9d orl %r8d, %eax movl %ecx, %r8d sall $4, %r9d sall $5, %r8d sall $6, %esi orl %r9d, %eax orl %r8d, %eax movl %ecx, %r8d orl %esi, %eax sall $7, %r8d orl %r8d, %eax kmovb %eax, %k1 we then get cmpl $3, %edi sete %cl negl %ecx kmovb %ecx, %k1 Code generation for non-uniform masks remains bad, but at least I see no easy way out for the most general case here. PR middle-end/110452 * expr.cc (store_constructor): Handle uniform boolean vectors with integer mode specially.
