https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111779
--- Comment #4 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:6decda1a35be5764101987c210b5693a0d914e58 commit r14-4612-g6decda1a35be5764101987c210b5693a0d914e58 Author: Richard Biener <rguent...@suse.de> Date: Thu Oct 12 11:34:57 2023 +0200 tree-optimization/111779 - Handle some BIT_FIELD_REFs in SRA The following handles byte-aligned, power-of-two and byte-multiple sized BIT_FIELD_REF reads in SRA. In particular this should cover BIT_FIELD_REFs created by optimize_bit_field_compare. For gcc.dg/tree-ssa/ssa-dse-26.c we now SRA the BIT_FIELD_REF appearing there leading to more DSE, fully eliding the aggregates. This results in the same false positive -Wuninitialized as the older attempt to remove the folding from optimize_bit_field_compare, fixed by initializing part of the aggregate unconditionally. PR tree-optimization/111779 gcc/ * tree-sra.cc (sra_handled_bf_read_p): New function. (build_access_from_expr_1): Handle some BIT_FIELD_REFs. (sra_modify_expr): Likewise. (make_fancy_name_1): Skip over BIT_FIELD_REF. gcc/fortran/ * trans-expr.cc (gfc_trans_assignment_1): Initialize lhs_caf_attr and rhs_caf_attr codimension flag to avoid false positive -Wuninitialized. gcc/testsuite/ * gcc.dg/tree-ssa/ssa-dse-26.c: Adjust for more DSE. * gcc.dg/vect/vect-pr111779.c: New testcase.