[Bug target/101845] New: wrong code at -O1 on aarch64 with __builtin_shufflevector()

[Bug target/101845] New: wrong code at -O1 on aarch64 with __builtin_shufflevector()

[zsojka at seznam dot cz]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101845

            Bug ID: 101845
           Summary: wrong code at -O1 on aarch64 with
                    __builtin_shufflevector()
           Product: gcc
           Version: 12.0
            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: aarch64-unknown-linux-gnu

Created attachment 51284
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=51284&action=edit
reduced testcase

Output:
$ aarch64-unknown-linux-gnu-gcc -O testcase.c -static
$ qemu-aarch64 -- ./a.out 
qemu: uncaught target signal 6 (Aborted) - core dumped
Aborted

foo:
        mvni    v0.2s, 0
        ret

just 0xffffffffffffffff is returned


$ aarch64-unknown-linux-gnu-gcc -v
Using built-in specs.
COLLECT_GCC=/repo/gcc-trunk/binary-latest-aarch64/bin/aarch64-unknown-linux-gnu-gcc
COLLECT_LTO_WRAPPER=/repo/gcc-trunk/binary-trunk-r12-2833-20210810162020-gc318f8e42b3-checking-yes-rtl-df-extra-aarch64/bin/../libexec/gcc/aarch64-unknown-linux-gnu/12.0.0/lto-wrapper
Target: aarch64-unknown-linux-gnu
Configured with: /repo/gcc-trunk//configure --enable-languages=c,c++
--enable-valgrind-annotations --disable-nls --enable-checking=yes,rtl,df,extra
--with-cloog --with-ppl --with-isl
--with-sysroot=/usr/aarch64-unknown-linux-gnu --build=x86_64-pc-linux-gnu
--host=x86_64-pc-linux-gnu --target=aarch64-unknown-linux-gnu
--with-ld=/usr/bin/aarch64-unknown-linux-gnu-ld
--with-as=/usr/bin/aarch64-unknown-linux-gnu-as --disable-libstdcxx-pch
--prefix=/repo/gcc-trunk//binary-trunk-r12-2833-20210810162020-gc318f8e42b3-checking-yes-rtl-df-extra-aarch64
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 12.0.0 20210810 (experimental) (GCC)

[Bug target/101845] wrong code at -O1 on aarch64 with __builtin_shufflevector()

[belagod at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101845

Tejas Belagod <belagod at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2021-08-11
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW
                 CC|                            |belagod at gcc dot gnu.org

--- Comment #1 from Tejas Belagod <belagod at gcc dot gnu.org> ---
Confirmed.

(insn 11 10 12 2 (set (reg:V8QI 92 [ _1 ])
        (mult:V8QI (reg:V8QI 100)
            (reg/v:V8QI 97 [ v ]))) "shuf.c":11:35 -1
     (nil))
(insn 12 11 13 2 (set (reg:V8QI 102)
        (const_vector:V8QI [
                (const_int -1 [0xffffffffffffffff]) repeated x8
            ])) -1
     (nil))

// Overwriting 92 [_1] looks suspicious?!
(insn 13 12 14 2 (set (subreg:V4HI (reg:V8QI 92 [ _1 ]) 0)
        (subreg:V4HI (reg:V8QI 102) 0)) -1
     (nil))

// Seems like merging 92 into itself leads to the wrong code...
(insn 14 13 15 2 (set (subreg:V4HI (reg:V8QI 92 [ _1 ]) 0)
        (vec_merge:V4HI (vec_duplicate:V4HI (vec_select:HI (subreg:V4HI
(reg:V8QI 92 [ _1 ]) 0)
                    (parallel [
                            (const_int 0 [0])
                        ])))
            (subreg:V4HI (reg:V8QI 92 [ _1 ]) 0)
            (const_int 1 [0x1]))) -1
     (nil))

[Bug target/101845] wrong code at -O1 on aarch64 with __builtin_shufflevector()

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101845

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |DUPLICATE

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
(In reply to Tejas Belagod from comment #1)
> Confirmed.
> 
> (insn 11 10 12 2 (set (reg:V8QI 92 [ _1 ])
>         (mult:V8QI (reg:V8QI 100)
>             (reg/v:V8QI 97 [ v ]))) "shuf.c":11:35 -1
>      (nil))
> (insn 12 11 13 2 (set (reg:V8QI 102)
>         (const_vector:V8QI [
>                 (const_int -1 [0xffffffffffffffff]) repeated x8
>             ])) -1
>      (nil))
> 
> // Overwriting 92 [_1] looks suspicious?!

Yes so it is the same problem as PR 101529.

*** This bug has been marked as a duplicate of bug 101529 ***