https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116274
--- Comment #10 from GCC 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:b8ea13ebf1211714503fd72f25c04376483bfa53 commit r15-3036-gb8ea13ebf1211714503fd72f25c04376483bfa53 Author: Richard Biener <rguent...@suse.de> Date: Thu Aug 8 11:36:43 2024 +0200 tree-optimization/116274 - overzealous SLP vectorization The following tries to address that the vectorizer fails to have precise knowledge of argument and return calling conventions and views some accesses as loads and stores that are not. This is mainly important when doing basic-block vectorization as otherwise loop indexing would force such arguments to memory. On x86 the reduction in the number of apparent loads and stores often dominates cost analysis so the following tries to mitigate this aggressively by adjusting only the scalar load and store cost, reducing them to the cost of a simple scalar statement, but not touching the vector access cost which would be much harder to estimate. Thereby we error on the side of not performing basic-block vectorization. PR tree-optimization/116274 * tree-vect-slp.cc (vect_bb_slp_scalar_cost): Cost scalar loads and stores as simple scalar stmts when they access a non-global, not address-taken variable that doesn't have BLKmode assigned. * gcc.target/i386/pr116274-2.c: New testcase.
