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From: "crazylht at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug rtl-optimization/110237] gcc.dg/torture/pr58955-2.c is
 miscompiled by RTL scheduling after reload
Date: Tue, 20 Jun 2023 11:35:31 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D110237

--- Comment #4 from Hongtao.liu <crazylht at gmail dot com> ---
(In reply to Richard Biener from comment #3)
> This looks like the same issue as PR110309.  We have
>=20
> (insn 38 35 39 3 (set (mem:V16SI (plus:DI (reg:DI 40 r12 [orig:90 _22 ] [=
90])
>                 (const:DI (plus:DI (symbol_ref:DI ("b") [flags 0x2]=20
> <var_decl 0x7ffff6e28d80 b>)
>                         (const_int -4 [0xfffffffffffffffc])))) [1 MEM
> <vector(16) int> [(int *)vectp_b.12_28]+0 S64 A32])
>         (vec_merge:V16SI (reg:V16SI 20 xmm0 [118])
>             (mem:V16SI (plus:DI (reg:DI 40 r12 [orig:90 _22 ] [90])=20
>                     (const:DI (plus:DI (symbol_ref:DI ("b") [flags 0x2]=20
> <var_decl 0x7ffff6e28d80 b>)
>                             (const_int -4 [0xfffffffffffffffc])))) [1 MEM
> <vector(16) int> [(int *)vectp_b.12_28]+0 S64 A32])
>=20
> so instead of a masked load we see a vec_merge with a (mem:V16SI ...)
> based on the vectp_b.12_28 pointer that has full size but the load of b[1]
> we try disambiguate against refers to int b[10] which is too small for
> a load of 64 bytes so we disambiguate based on that.


  /* If the pointer based access is bigger than the variable they cannot
     alias.  This is similar to the check below where we use TBAA to
     increase the size of the pointer based access based on the dynamic
     type of a containing object we can infer from it.  */
  poly_int64 dsize2;
  if (known_size_p (size1) --- should be unknown??
      && poly_int_tree_p (DECL_SIZE (base2), &dsize2)
      && known_lt (dsize2, size1))
    return false;

Should we set MEM_SIZE_KNOWN_P to false for maskstore/maskload?
It seems to me maxsize should be 64bytes, but real size should be unknown.=