https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102682
--- 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:147ed0184f403b51b4f180f94b0779e9905faa3a commit r12-4428-g147ed0184f403b51b4f180f94b0779e9905faa3a Author: Richard Biener <rguent...@suse.de> Date: Mon Oct 11 14:08:52 2021 +0200 middle-end/102682 - avoid invalid subreg on the LHS The following avoids generating (insn 6 5 7 2 (set (subreg:OI (concatn/v:TI [ (reg:DI 92 [ buffer ]) (reg:DI 93 [ buffer+8 ]) ]) 0) (subreg:OI (reg/v:V8SI 85 [ __x ]) 0)) "t.ii":76:21 74 {*movoi_internal_avx} (nil)) via store_bit_field_1 when we try to store excess data into a register allocated temporary. The case was supposed to /* Use the subreg machinery either to narrow OP0 to the required words... but the check ensured only an register-aligned but not a large enough piece. The following adds such missed check which ends up decomposing the set to (insn 6 5 7 (set (subreg:DI (reg/v:TI 84 [ buffer ]) 0) (subreg:DI (reg/v:V8SI 85 [ __x ]) 0)) "t.ii":76:21 -1 (nil)) (insn 7 6 0 (set (subreg:DI (reg/v:TI 84 [ buffer ]) 8) (subreg:DI (reg/v:V8SI 85 [ __x ]) 8)) "t.ii":76:21 -1 (nil)) 2021-10-11 Richard Biener <rguent...@suse.de> PR middle-end/102682 * expmed.c (store_bit_field_1): Ensure a LHS subreg would not create a paradoxical subreg.
