https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107240
--- Comment #9 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Kewen Lin <li...@gcc.gnu.org>: https://gcc.gnu.org/g:5d6e834ecf212e7fc6f585b154af224d2e38c749 commit r13-3396-g5d6e834ecf212e7fc6f585b154af224d2e38c749 Author: Kewen Lin <li...@linux.ibm.com> Date: Thu Oct 20 04:07:05 2022 -0500 vect: Simplify first for shifted value generation [PR107240] As PR107240 shows, when both the value to be shifted and the count used for shifting are constants, it can be simplified to one constant value, and doesn't actually require to check if the current target supports vector shift operations or not. This patch uses a canonical way proposed by Richi to generate the shifted value, if it can be simplified, the shift operation would be gone, otherwise it's the same as before. It can help to fix the failures of vect-bitfield-write-{2,3}.c on Power. PR tree-optimization/107240 2022-10-20 Richard Biener <rguent...@suse.de> gcc/ChangeLog: * tree-vect-patterns.cc (vect_recog_bit_insert_pattern): Attempt to simplify shifted value first.