https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109109
--- Comment #19 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:42630fadbe248717859d61c0244c821c32b4e52c commit r13-6669-g42630fadbe248717859d61c0244c821c32b4e52c Author: Jakub Jelinek <ja...@redhat.com> Date: Tue Mar 14 19:20:23 2023 +0100 i386: Fix up split_double_concat [PR109109] In my PR107627 change I've missed one important case, which causes miscompilation of f4 and f6 in the following tests. Combine matches there *concatsidi3_3 define_insn_and_split (as with all other f* functions in those tests), and RA ends up with: (insn 11 10 17 2 (set (reg:DI 0 ax [89]) (ior:DI (ashift:DI (zero_extend:DI (mem:SI (plus:SI (mult:SI (reg:SI 0 ax [94]) (const_int 4 [0x4])) (symbol_ref:SI ("arr") [flags 0x2] <var_decl 0x7f4e7fe4ccf0 arr>)) [1 arr[ax_6(D)]+0 S4 A32])) (const_int 32 [0x20])) (zero_extend:DI (reg:SI 1 dx [95])))) "pr109109-6.c":24:49 681 {*concatsidi3_3} (nil)) split_double_concat turned that into: movl arr(,%eax,4), %edx movl %edx, %eax which is incorrect, because the first instruction overrides the input %edx value that should be put into output %eax; the two insns can't be swapped because the MEM's address uses %eax. The following patch fixes that case to emit movl arr(,%eax,4), %eax xchgl %edx, %eax instead. 2023-03-14 Jakub Jelinek <ja...@redhat.com> PR target/109109 * config/i386/i386-expand.cc (split_double_concat): Fix splitting when lo is equal to dhi and hi is a MEM which uses dlo register. * gcc.target/i386/pr109109-1.c: New test. * gcc.target/i386/pr109109-2.c: New test.
