On Fri, Mar 15, 2024 at 9:50 AM Jakub Jelinek <ja...@redhat.com> wrote:
>
> Hi!
>
> In r13-3803-gfa271afb58 I've added an optimization for LE/LEU/GE/GEU
> comparison against CONST_VECTOR. As the comments say:
> /* x <= cst can be handled as x < cst + 1 unless there is
> wrap around in cst + 1. */
> ...
> /* For LE punt if some element is signed maximum. */
> ...
> /* For LEU punt if some element is unsigned maximum. */
> and
> /* x >= cst can be handled as x > cst - 1 unless there is
> wrap around in cst - 1. */
> ...
> /* For GE punt if some element is signed minimum. */
> ...
> /* For GEU punt if some element is zero. */
> Apparently I wrote the GE/GEU (second case) first and then
> copied/adjusted it for LE/LEU, most of the adjustments look correct, but
> I've left if (code == GE) comparison when testing if it should punt for
> signed maximum. That condition is never true, because this is in
> switch (code) { ... case LE: case LEU: block and we really meant to
> be what the comment says, for LE punt if some element is signed maximum,
> as then cst + 1 wraps around.
>
> The following patch fixes the pasto.
>
> Bootstrapped/regtested on x86_64-linux and i686-linux, ok for trunk?
>
> 2024-03-15 Jakub Jelinek <ja...@redhat.com>
>
> PR target/114339
> * config/i386/i386-expand.cc (ix86_expand_int_sse_cmp) <case LE>: Fix
> a pasto, compare code against LE rather than GE.
>
> * gcc.target/i386/pr114339.c: New test.
OK.
Thanks,
Uros.
>
> --- gcc/config/i386/i386-expand.cc.jj 2024-03-07 08:34:21.043802912 +0100
> +++ gcc/config/i386/i386-expand.cc 2024-03-14 22:55:57.321842686 +0100
> @@ -4690,7 +4690,7 @@ ix86_expand_int_sse_cmp (rtx dest, enum
> rtx elt = CONST_VECTOR_ELT (cop1, i);
> if (!CONST_INT_P (elt))
> break;
> - if (code == GE)
> + if (code == LE)
> {
> /* For LE punt if some element is signed maximum. */
> if ((INTVAL (elt) & (GET_MODE_MASK (eltmode) >> 1))
> --- gcc/testsuite/gcc.target/i386/pr114339.c.jj 2024-03-14 22:58:04.739076025
> +0100
> +++ gcc/testsuite/gcc.target/i386/pr114339.c 2024-03-14 22:38:59.736972124
> +0100
> @@ -0,0 +1,20 @@
> +/* PR target/114339 */
> +/* { dg-do run } */
> +/* { dg-options "-O2 -Wno-psabi" } */
> +/* { dg-additional-options "-mavx" { target avx_runtime } } */
> +
> +typedef long long V __attribute__((vector_size (16)));
> +
> +__attribute__((noipa)) V
> +foo (V a)
> +{
> + return a <= (V) {0, __LONG_LONG_MAX__ };
> +}
> +
> +int
> +main ()
> +{
> + V t = foo ((V) { 0, 0 });
> + if (t[0] != -1LL || t[1] != -1LL)
> + __builtin_abort ();
> +}
>
> Jakub
>
