[Bug target/112672] New: [14 Regression] wrong code with __builtin_parityl() at -O and above on x86_64

[Bug target/112672] New: [14 Regression] wrong code with __builtin_parityl() at -O and above on x86_64

[zsojka at seznam dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112672

            Bug ID: 112672
           Summary: [14 Regression] wrong code with __builtin_parityl() at
                    -O and above on x86_64
           Product: gcc
           Version: 14.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: zsojka at seznam dot cz
  Target Milestone: ---
              Host: x86_64-pc-linux-gnu
            Target: x86_64-pc-linux-gnu

Created attachment 56666
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=56666&action=edit
reduced testcase

Output:
$ x86_64-pc-linux-gnu-gcc -O testcase.c
$ ./a.out 
Aborted

$ x86_64-pc-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=/repo/gcc-trunk/binary-latest-amd64/bin/x86_64-pc-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/repo/gcc-trunk/binary-trunk-r14-5761-20231122145100-ge9b39df9333-checking-yes-rtl-df-extra-nobootstrap-amd64/bin/../libexec/gcc/x86_64-pc-linux-gnu/14.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: /repo/gcc-trunk//configure --enable-languages=c,c++
--enable-valgrind-annotations --disable-nls --enable-checking=yes,rtl,df,extra
--disable-bootstrap --with-cloog --with-ppl --with-isl
--build=x86_64-pc-linux-gnu --host=x86_64-pc-linux-gnu
--target=x86_64-pc-linux-gnu --with-ld=/usr/bin/x86_64-pc-linux-gnu-ld
--with-as=/usr/bin/x86_64-pc-linux-gnu-as --disable-libstdcxx-pch
--prefix=/repo/gcc-trunk//binary-trunk-r14-5761-20231122145100-ge9b39df9333-checking-yes-rtl-df-extra-nobootstrap-amd64
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 14.0.0 20231122 (experimental) (GCC) 

At the asm output, the problem is obvious:

main:
# testcase.c:8:   u *= g;
        movzx   eax, WORD PTR g[rip]    # tmp110, g
        sal     eax, 2  # u,
# testcase.c:9:   return u + __builtin_parityl (u);
        xor     al, ah  # u <== THIS OVERWRITES "u" in eax
        setnp   dl      #, tmp105
        movzx   edx, dl # tmp105, tmp105
# testcase.c:9:   return u + __builtin_parityl (u);
        add     eax, edx        # tmp107, tmp105 <== THIS READ "u", but it has
been lost
# testcase.c:16:   if (x != 4 * 254 + 1)
        cmp     ax, 1017        # tmp107,
        jne     .L6     #,
# testcase.c:19: }
        mov     eax, 0  #,
        ret

[Bug target/112672] [14 Regression] wrong code with __builtin_parityl() at -O and above on x86_64

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112672

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |14.0
                 CC|                            |pinskia at gcc dot gnu.org

[Bug target/112672] [14 Regression] wrong code with __builtin_parityl() at -O and above on x86_64

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112672

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2023-11-23
     Ever confirmed|0                           |1

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Obvious this is wrong:
;; _5 = .PARITY (u_4);

(insn 7 6 8 (parallel [
            (set (reg:CC 17 flags)
                (unspec:CC [
                        (reg/v:HI 99 [ uD.2808 ])
                    ] UNSPEC_PARITY))
            (clobber (reg/v:HI 99 [ uD.2808 ]))
        ]) "/app/example.cpp":9:32 -1
     (nil))
...
;; if (_7 != 1017)

(insn 11 10 12 (parallel [
            (set (reg:HI 107)
                (plus:HI (reg/v:HI 99 [ uD.2808 ])
                    (subreg:HI (reg:SI 100 [ _5 ]) 0)))
            (clobber (reg:CC 17 flags))
        ]) "/app/example.cpp":9:34 discrim 1 -1
     (nil))

[Bug target/112672] [14 Regression] wrong code with __builtin_parityl() at -O and above on x86_64

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112672

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |uros at gcc dot gnu.org

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Actually it has been wrong since r11-1027-gf08995eefbf579 . Just exposed by
Jakub's parity improvement: r14-5557-g6dd4c703be17fa .

[Bug target/112672] [14 Regression] wrong code with __builtin_parityl() at -O and above on x86_64

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112672

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
parityhi2 should have:
rtx extra = gen_reg_rtx (HImode);
emit_move_insn (extra, operands[1]);
emit_insn (gen_parityhi2_cmp (extra));

Or something similar because parityqi2_cmp clobbers its argument.

[Bug target/112672] [14 Regression] wrong code with __builtin_parityl() at -O and above on x86_64

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112672

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P1

[Bug target/112672] [14 Regression] wrong code with __builtin_parityl() at -O and above on x86_64

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112672

Uroš Bizjak <ubizjak at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
           Assignee|unassigned at gcc dot gnu.org      |ubizjak at gmail dot com

--- Comment #4 from Uroš Bizjak <ubizjak at gmail dot com> ---
(In reply to Andrew Pinski from comment #3)
> parityhi2 should have:
> rtx extra = gen_reg_rtx (HImode);
> emit_move_insn (extra, operands[1]);
> emit_insn (gen_parityhi2_cmp (extra));
> 
> Or something similar because parityqi2_cmp clobbers its argument.

Exactly.

I have a patch in testing.

[Bug target/112672] [14 Regression] wrong code with __builtin_parityl() at -O and above on x86_64

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112672

--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Uros Bizjak <uros@gcc.gnu.org>:

https://gcc.gnu.org/g:b2d17bdd45b582b93e89c00b04763a45f97d7a34

commit r14-5785-gb2d17bdd45b582b93e89c00b04763a45f97d7a34
Author: Uros Bizjak <ubizjak@gmail.com>
Date:   Thu Nov 23 16:17:57 2023 +0100

    i386: Wrong code with __builtin_parityl [PR112672]

    gen_parityhi2_cmp instruction clobbers its input operand, so use
    a temporary register in the call to gen_parityhi2_cmp.

            PR target/112672

    gcc/ChangeLog:

            * config/i386/i386.md (parityhi2):
            Use temporary register in the call to gen_parityhi2_cmp.

    gcc/testsuite/ChangeLog:

            * gcc.target/i386/pr112672.c: New test.

[Bug target/112672] [14 Regression] wrong code with __builtin_parityl() at -O and above on x86_64

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112672

--- Comment #6 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-13 branch has been updated by Uros Bizjak <uros@gcc.gnu.org>:

https://gcc.gnu.org/g:d035b57d51167af805ccc91ee0492c8b27e22184

commit r13-8092-gd035b57d51167af805ccc91ee0492c8b27e22184
Author: Uros Bizjak <ubizjak@gmail.com>
Date:   Thu Nov 23 16:17:57 2023 +0100

    i386: Wrong code with __builtin_parityl [PR112672]

    gen_parityhi2_cmp instruction clobbers its input operand, so use
    a temporary register in the call to gen_parityhi2_cmp.

            PR target/112672

    gcc/ChangeLog:

            * config/i386/i386.md (parityhi2):
            Use temporary register in the call to gen_parityhi2_cmp.

    gcc/testsuite/ChangeLog:

            * gcc.target/i386/pr112672.c: New test.

    (cherry picked from commit b2d17bdd45b582b93e89c00b04763a45f97d7a34)

[Bug target/112672] [14 Regression] wrong code with __builtin_parityl() at -O and above on x86_64

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112672

--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-12 branch has been updated by Uros Bizjak <uros@gcc.gnu.org>:

https://gcc.gnu.org/g:f0445f4401c941d0aa3cc413ca4548f313cc1257

commit r12-10001-gf0445f4401c941d0aa3cc413ca4548f313cc1257
Author: Uros Bizjak <ubizjak@gmail.com>
Date:   Thu Nov 23 16:17:57 2023 +0100

    i386: Wrong code with __builtin_parityl [PR112672]

    gen_parityhi2_cmp instruction clobbers its input operand, so use
    a temporary register in the call to gen_parityhi2_cmp.

            PR target/112672

    gcc/ChangeLog:

            * config/i386/i386.md (parityhi2):
            Use temporary register in the call to gen_parityhi2_cmp.

    gcc/testsuite/ChangeLog:

            * gcc.target/i386/pr112672.c: New test.

    (cherry picked from commit b2d17bdd45b582b93e89c00b04763a45f97d7a34)

[Bug target/112672] [14 Regression] wrong code with __builtin_parityl() at -O and above on x86_64

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112672

--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Uros Bizjak <uros@gcc.gnu.org>:

https://gcc.gnu.org/g:422e30e4d5ca2f26f77e7c90e09658408c07a23c

commit r11-11111-g422e30e4d5ca2f26f77e7c90e09658408c07a23c
Author: Uros Bizjak <ubizjak@gmail.com>
Date:   Thu Nov 23 16:17:57 2023 +0100

    i386: Wrong code with __builtin_parityl [PR112672]

    gen_parityhi2_cmp instruction clobbers its input operand, so use
    a temporary register in the call to gen_parityhi2_cmp.

            PR target/112672

    gcc/ChangeLog:

            * config/i386/i386.md (parityhi2):
            Use temporary register in the call to gen_parityhi2_cmp.

    gcc/testsuite/ChangeLog:

            * gcc.target/i386/pr112672.c: New test.

    (cherry picked from commit b2d17bdd45b582b93e89c00b04763a45f97d7a34)

[Bug target/112672] [14 Regression] wrong code with __builtin_parityl() at -O and above on x86_64

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112672

Uroš Bizjak <ubizjak at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|14.0                        |11.5

--- Comment #9 from Uroš Bizjak <ubizjak at gmail dot com> ---
Fixed everywhere.

[Bug target/112672] [14 Regression] wrong code with __builtin_parityl() at -O and above on x86_64

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112672

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Resolution|---                         |FIXED
             Status|ASSIGNED                    |RESOLVED

--- Comment #10 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
.