On Wed, Apr 13, 2022 at 9:07 AM Hongyu Wang <hongyu.w...@intel.com> wrote:
>
> Hi,
>
> For -mrelax-cmpxchg-loop which relaxes atomic_fetch_<logic> loops,
> there is a missing set to %eax when compare fails, which would result
> in infinite loop in some benchmark. Add set to %eax to avoid it.
>
> Bootstraped/regtested on x86_64-pc-linux-gnu{-m32,}
>
> Ok for master?
>
> gcc/ChangeLog:
>
> PR target/103069
> * config/i386/i386-expand.cc (ix86_expand_cmpxchg_loop):
> Add missing set to target_val at pause label.
LGTM.
Uros.
> ---
> gcc/config/i386/i386-expand.cc | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/gcc/config/i386/i386-expand.cc b/gcc/config/i386/i386-expand.cc
> index 794315ee2f7..2144d3f968d 100644
> --- a/gcc/config/i386/i386-expand.cc
> +++ b/gcc/config/i386/i386-expand.cc
> @@ -23388,6 +23388,7 @@ void ix86_expand_cmpxchg_loop (rtx *ptarget_bool, rtx
> target_val,
>
> /* If mem is not expected, pause and loop back. */
> emit_label (cmp_label);
> + emit_move_insn (target_val, new_mem);
> emit_insn (gen_pause ());
> emit_jump_insn (gen_jump (loop_label));
> emit_barrier ();
> --
> 2.18.1
>
