On Tue, Aug 5, 2025 at 3:32 PM H.J. Lu <hjl.to...@gmail.com> wrote:
>
> commit 050b1708ea532ea4840e97d85fad4ca63d4cd631
> Author: H.J. Lu <hjl.to...@gmail.com>
> Date: Thu Jun 19 05:03:48 2025 +0800
>
> x86: Get the widest vector mode from MOVE_MAX
>
> gets the widest vector mode from MOVE_MAX. But for memset, it should
> use STORE_MAX_PIECES.
>
> gcc/
>
> PR target/121410
> * config/i386/i386-expand.cc (ix86_expand_set_or_cpymem): Use
> STORE_MAX_PIECES to get the widest vector mode in vector loop
> for memset.
>
> gcc/testsuite/
>
> PR target/121410
> * gcc.target/i386/pr121410.c: New test.
OK with a small cosmetic change suggested below.
Thanks,
Uros.
>
> Signed-off-by: H.J. Lu <hjl.to...@gmail.com>
> ---
> gcc/config/i386/i386-expand.cc | 5 +++--
> gcc/testsuite/gcc.target/i386/pr121410.c | 11 +++++++++++
> 2 files changed, 14 insertions(+), 2 deletions(-)
> create mode 100644 gcc/testsuite/gcc.target/i386/pr121410.c
>
> diff --git a/gcc/config/i386/i386-expand.cc b/gcc/config/i386/i386-expand.cc
> index 0e5af5319ff..a5527081d9e 100644
> --- a/gcc/config/i386/i386-expand.cc
> +++ b/gcc/config/i386/i386-expand.cc
> @@ -9574,8 +9574,9 @@ ix86_expand_set_or_cpymem (rtx dst, rtx src, rtx
> count_exp, rtx val_exp,
> case vector_loop:
> need_zero_guard = true;
> unroll_factor = 4;
> - /* Get the vector mode to move MOVE_MAX bytes. */
> - nunits = MOVE_MAX / GET_MODE_SIZE (word_mode);
> + /* Get the vector mode to move STORE_MAX_PIECES/MOVE_MAX bytes. */
> + nunits = ((issetmem ? STORE_MAX_PIECES : MOVE_MAX)
Please put the number of bytes into a temporary.
> + / GET_MODE_SIZE (word_mode));
> if (nunits > 1)
> {
> move_mode = mode_for_vector (word_mode, nunits).require ();
> diff --git a/gcc/testsuite/gcc.target/i386/pr121410.c
> b/gcc/testsuite/gcc.target/i386/pr121410.c
> new file mode 100644
> index 00000000000..04bab91e1b8
> --- /dev/null
> +++ b/gcc/testsuite/gcc.target/i386/pr121410.c
> @@ -0,0 +1,11 @@
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -march=x86-64 -mavx512f -mstore-max=128" } */
> +
> +extern unsigned _BitInt(3719) a;
> +extern _BitInt(465) g;
> +void
> +foo(void)
> +{
> + _BitInt(465) b = a >> 1860;
> + g = b + b;
> +}
> --
> 2.50.1
>
