https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101801
--- Comment #7 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:19d1a529fa9f78e7ec7be38d423c90e00cec8f8c commit r12-2832-g19d1a529fa9f78e7ec7be38d423c90e00cec8f8c Author: Richard Biener <rguent...@suse.de> Date: Mon Aug 9 11:42:47 2021 +0200 tree-optimization/101801 - rework generic vector vectorization more This builds ontop of the vect_worthwhile_without_simd_p refactoring done earlier. It was wrong in dropping the appearant double checks for operation support since the optab check can happen with an integer vector emulation mode and thus succeed but vector lowering might not actually support the operation on word_mode. The following patch adds a vect_emulated_vector_p helper and re-instantiates the check where it was previously. It also adds appropriate costing of the scalar stmts emitted by vector lowering to vectorizable_operation which should be the only place such operations are synthesized. I've also cared for the case where the vector mode is supported but the operation is not (though I think this will be unlikely given we're talking about plus, minus and negate). This fixes the observed FAIL of gcc.dg/tree-ssa/gen-vect-11b.c with -m32 where we end up vectorizing a multiplication that ends up being teared down to scalars again by vector lowering. I'm not super happy about all the other places where we're now and previously feeding scalar modes to optab checks where we want to know whether we can vectorize sth but well. 2021-09-08 Richard Biener <rguent...@suse.de> PR tree-optimization/101801 PR tree-optimization/101819 * tree-vectorizer.h (vect_emulated_vector_p): Declare. * tree-vect-loop.c (vect_emulated_vector_p): New function. (vectorizable_reduction): Re-instantiate a check for emulated operations. * tree-vect-stmts.c (vectorizable_shift): Likewise. (vectorizable_operation): Likewise. Cost emulated vector operations according to the scalar sequence synthesized by vector lowering.
