https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100089
--- Comment #12 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:199cd0e0f8744ca1e61a95987b2d020a592a46d9 commit r12-6795-g199cd0e0f8744ca1e61a95987b2d020a592a46d9 Author: Richard Biener <rguent...@suse.de> Date: Fri Jan 21 13:29:06 2022 +0100 tree-optimization/100089 - BB vectorization of if-converted loop bodies The PR complains that when we only partially BB vectorize an if-converted loop body that this can leave unvectorized code unconditionally executed and thus effectively slow down code. For -O2 we already mitigated the issue by not doing BB vectorization when not all if-converted stmts were covered but the issue is present with -O3 as well. Thus the following simply extends the fix to cover all but the unlimited cost models. It is after all very likely that we vectorize some stmts, if only a single paired store. 2022-01-21 Richard Biener <rguent...@suse.de> PR tree-optimization/100089 * tree-vect-slp.cc (vect_slp_region): Reject BB vectorization of if-converted loops with unvectorized COND_EXPRs for all but the unlimited cost models.
