https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61747
--- Comment #8 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:ceae1400cf24f329393e96dd9720b0391afe858d commit r14-2667-gceae1400cf24f329393e96dd9720b0391afe858d Author: Richard Biener <rguent...@suse.de> Date: Tue Jul 18 13:19:11 2023 +0200 middle-end/61747 - conditional move expansion and constants When expanding a COND_EXPR or a VEC_COND_EXPR the x86 backend for example tries to match FP min/max instructions. But this only works when it can see the equality of the comparison and selected operands. This breaks in both prepare_cmp_insn and vector_compare_rtx where the former forces expensive constants to a register and the latter performs legitimization. The patch below fixes this in the caller preserving former equalities. PR middle-end/61747 * internal-fn.cc (expand_vec_cond_optab_fn): When the value operands are equal to the original comparison operands preserve that equality by re-using the comparison expansion. * optabs.cc (emit_conditional_move): When the value operands are equal to the comparison operands and would be forced to a register by prepare_cmp_insn do so earlier, preserving the equality. * g++.target/i386/pr61747.C: New testcase.
