[Bug target/109109] [13 Regression] mariadb fails in tests on i586 (non-LTO mode) after r13-4435-g2c089640279614e3

[cvs-commit at gcc dot gnu.org]

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 <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:42630fadbe248717859d61c0244c821c32b4e52c

commit r13-6669-g42630fadbe248717859d61c0244c821c32b4e52c
Author: Jakub Jelinek <jakub@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  <jakub@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.