[Bug middle-end/100738] New: Gimple failed to simplify ((v4si) ~a) < 0 ? c : d to ((v4si)a) >= 0 ? c : d

[Bug middle-end/100738] New: Gimple failed to simplify ((v4si) ~a) < 0 ? c : d to ((v4si)a) >= 0 ? c : d

[crazylht at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100738

            Bug ID: 100738
           Summary: Gimple failed to simplify ((v4si) ~a) < 0 ? c : d to
                    ((v4si)a) >= 0 ? c : d
           Product: gcc
           Version: 12.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
          Assignee: unassigned at gcc dot gnu.org
          Reporter: crazylht at gmail dot com
                CC: hjl.tools at gmail dot com
  Target Milestone: ---
              Host: x86_64-pc-linux-gnu
            Target: x86_64-*-* i?86-*-*

cat test.c



typedef int v4si __attribute__((vector_size (16)));
typedef char v16qi __attribute__((vector_size (16)));
v4si
foo (v16qi a, v4si b, v4si c, v4si d)
{
    return ((v4si)~a) < 0 ? c : d;
}

gcc -Ofast -mavx2

foo(char __vector(16), int __vector(4), int __vector(4), int __vector(4)):
        vpcmpeqd        %xmm1, %xmm1, %xmm1
        vpxor   %xmm1, %xmm0, %xmm0
        vblendvps       %xmm0, %xmm2, %xmm3, %xmm0
        ret

it can be better with 

        vblendvps       xmm0, xmm3, xmm2, xmm0

gimple failed to simplify  ((v4si)~a) < 0 ? c : d to ((v4si)a) >= 0 ? c : d

With https://gcc.gnu.org/pipermail/gcc-patches/2021-May/571056.html, i observe
rtl also won't simplify things like (vec_merge op1 op2 (lt (subreg （not op3) 0)
const0_rtx)) to (vec_merge op2 op1 (lt (subreg op3 0) const0_rtx))

[Bug middle-end/100738] Gimple failed to simplify ((v4si) ~a) < 0 ? c : d to ((v4si)a) >= 0 ? c : d

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100738

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |missed-optimization
           Severity|normal                      |enhancement

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
One thing is VCE<~A> should be converted to ~VCE<A> which might allow ~B < 0 to
be converted to B >= 0.

On RTL, it might be useful to still simplify:
(subreg （not op3) 0)
To:
(not (subreg op3 0))

[Bug middle-end/100738] Gimple failed to simplify ((v4si) ~a) < 0 ? c : d to ((v4si)a) >= 0 ? c : d

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100738

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1
   Last reconfirmed|                            |2021-05-25

--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.  Watch out for (v4sf)~a though.  Note there's
~(v4si)(a ^ b) to be considered - outer not and inner bitops which could
be combined (likewise inner not and outer bitops).  So any canonicalization
will miss sth which means consumers should rather be prepared to handle
both 'a' and '(v4si)a'.

[Bug middle-end/100738] Gimple failed to simplify ((v4si) ~a) < 0 ? c : d to ((v4si)a) >= 0 ? c : d

[crazylht at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100738

--- Comment #3 from Hongtao.liu <crazylht at gmail dot com> ---
(In reply to Richard Biener from comment #2)
> Confirmed.  Watch out for (v4sf)~a though.  Note there's
Not sure for (v4sf)~a if we honor NANs, (v4sf)~a < 0 could be different from
(v4sf)a >= 0;

[Bug middle-end/100738] Gimple failed to simplify ((v4si) ~a) < 0 ? c : d to ((v4si)a) >= 0 ? c : d

[crazylht at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100738

--- Comment #4 from Hongtao.liu <crazylht at gmail dot com> ---
(In reply to Richard Biener from comment #2)
> Confirmed.  Watch out for (v4sf)~a though.  Note there's
> ~(v4si)(a ^ b) to be considered - outer not and inner bitops which could
> be combined (likewise inner not and outer bitops).  

It seems we prefer out not.

/* Otherwise prefer ~(X ^ Y) to ~X ^ Y as more canonical.  */
(simplify
 (bit_xor:c (nop_convert?:s (bit_not:s @0)) @1)
 (if (tree_nop_conversion_p (type, TREE_TYPE (@0)))
  (bit_not (bit_xor (view_convert @0) @1))))

[Bug middle-end/100738] Gimple failed to simplify ((v4si) ~a) < 0 ? c : d to ((v4si)a) >= 0 ? c : d

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100738

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

https://gcc.gnu.org/g:691f05c2197a7b79cb2d7fdbabe3182e22da320a

commit r12-5832-g691f05c2197a7b79cb2d7fdbabe3182e22da320a
Author: Haochen Jiang <haochen.jiang@intel.com>
Date:   Thu Dec 2 15:30:17 2021 +0800

    Add combine splitter to transform vpcmpeqd/vpxor/vblendvps to vblendvps for
~op0

    gcc/ChangeLog:

            PR target/100738
            * config/i386/sse.md
            (*<sse4_1>_blendv<ssefltmodesuffix><avxsizesuffix>_not_ltint):
            Add new define_insn_and_split.

    gcc/testsuite/ChangeLog:

            PR target/100738
            * g++.target/i386/pr100738-1.C: New test.

[Bug middle-end/100738] Gimple failed to simplify ((v4si) ~a) < 0 ? c : d to ((v4si)a) >= 0 ? c : d

[crazylht at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100738

Hongtao.liu <crazylht at gmail dot com> changed:

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

--- Comment #6 from Hongtao.liu <crazylht at gmail dot com> ---
Fixed in GCC12 in the backend.

[Bug middle-end/100738] Gimple failed to simplify ((v4si) ~a) < 0 ? c : d to ((v4si)a) >= 0 ? c : d

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100738

--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by hongtao Liu <liuhongt@gcc.gnu.org>:

https://gcc.gnu.org/g:456b53654a3e3cc550c24f2cb0e37e7fdfadf68e

commit r12-6032-g456b53654a3e3cc550c24f2cb0e37e7fdfadf68e
Author: Haochen Jiang <haochen.jiang@intel.com>
Date:   Thu Dec 2 15:30:17 2021 +0800

    Add combine splitter to transform vpternlogd/vpcmpeqd/vpxor/vblendvps to
vblendvps for ~op0

    gcc/ChangeLog:

            PR target/100738
            * config/i386/sse.md (*avx_cmp<mode>3_lt, *avx_cmp<mode>3_ltint):
            Remove MEM_P restriction and add force_reg for operands[2].
            (*avx_cmp<mode>3_ltint_not): Add new define_insn_and_split.

    gcc/testsuite/ChangeLog:

            PR target/100738
            * g++.target/i386/avx512vl-pr100738-1.C: New test.