https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93582
--- Comment #25 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:8aba425f4ebc5e2c054776d3cdddf13f7c1918f8 commit r10-6614-g8aba425f4ebc5e2c054776d3cdddf13f7c1918f8 Author: Jakub Jelinek <ja...@redhat.com> Date: Thu Feb 13 10:04:11 2020 +0100 sccvn: Handle bitfields in vn_reference_lookup_3 [PR93582] The following patch is first step towards fixing PR93582. vn_reference_lookup_3 right now punts on anything that isn't byte aligned, so to be able to lookup a constant bitfield store, one needs to use the exact same COMPONENT_REF, otherwise it isn't found. This patch lifts up that that restriction if the bits to be loaded are covered by a single store of a constant (keeps the restriction so far for the multiple store case, can tweak that incrementally, but I think for bisection etc. it is worth to do it one step at a time). 2020-02-13 Jakub Jelinek <ja...@redhat.com> PR tree-optimization/93582 * fold-const.h (shift_bytes_in_array_left, shift_bytes_in_array_right): Declare. * fold-const.c (shift_bytes_in_array_left, shift_bytes_in_array_right): New function, moved from gimple-ssa-store-merging.c, no longer static. * gimple-ssa-store-merging.c (shift_bytes_in_array): Move to gimple-ssa-store-merging.c and rename to shift_bytes_in_array_left. (shift_bytes_in_array_right): Move to gimple-ssa-store-merging.c. (encode_tree_to_bitpos): Use shift_bytes_in_array_left instead of shift_bytes_in_array. (verify_shift_bytes_in_array): Rename to ... (verify_shift_bytes_in_array_left): ... this. Use shift_bytes_in_array_left instead of shift_bytes_in_array. (store_merging_c_tests): Call verify_shift_bytes_in_array_left instead of verify_shift_bytes_in_array. * tree-ssa-sccvn.c (vn_reference_lookup_3): For native_encode_expr / native_interpret_expr where the store covers all needed bits, punt on PDP-endian, otherwise allow all involved offsets and sizes not to be byte-aligned. * gcc.dg/tree-ssa/pr93582-1.c: New test. * gcc.dg/tree-ssa/pr93582-2.c: New test. * gcc.dg/tree-ssa/pr93582-3.c: New test.
