Andrew Pinski <quic_apin...@quicinc.com> writes:
> r15-6789-ge7f98d9603808b added a new RTL pass for hardreg PRE for the hard
> register
> of FPM_REGNUM, but this pass does nothing if there can be any FPM_REGNUM
> register in it.
> So let's set HARDREG_PRE_REGNOS to include all zeros if !TARGET_FP8.
> Now the pass will only run if there is a possibility of having the FPM
> register.
Could we get most of the benefit by instead adding:
if (!df_regs_ever_live_p (current_hardreg_regno))
continue;
to the pass loop? I think we could do it even before df_analyze given
the optimize > 0 gate.
If so, we'd also get the benefit for TARGET_FP8 in functions that don't
use FP8 intrinsics.
Thanks,
Richard
> Built and tested for aarch64-linux-gnu.
>
> PR target/121095
> gcc/ChangeLog:
>
> * config/aarch64/aarch64.h (HARDREG_PRE_REGNOS): Don't include
> FPM_REGNUM
> if !TARGET_FP8.
>
> Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
> ---
> gcc/config/aarch64/aarch64.h | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/gcc/config/aarch64/aarch64.h b/gcc/config/aarch64/aarch64.h
> index 096c853af7f..d128ed726f0 100644
> --- a/gcc/config/aarch64/aarch64.h
> +++ b/gcc/config/aarch64/aarch64.h
> @@ -1661,8 +1661,8 @@ enum class aarch64_tristate_mode : int { NO, YES, MAYBE
> };
> int (aarch64_local_sme_state::ANY) }
>
> /* Zero terminated list of regnos for which hardreg PRE should be
> - applied. */
> -#define HARDREG_PRE_REGNOS { FPM_REGNUM, 0 }
> + applied. Only enable FPM reg if FP8 is enabled. */
> +#define HARDREG_PRE_REGNOS { TARGET_FP8 ? FPM_REGNUM : 0, 0 }
>
> #endif
