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, this pass could get expensive if you have a large number of
> basic blocks
> and the hard register was never alive so it does nothing in the end.
> In the aarch64 case, FPM_REGNUM is only used for FP8 related code so it has a
> high probability
> of not being used. So skipping the pass for that register can improve both
> compile time and memory
> usage.
>
> Build and tested for aarch64-linux-gnu.
>
> PR middle-end/PR121095
> gcc/ChangeLog:
>
> * gcse.cc (execute_hardreg_pre): Skip if the hardreg is never alive.
>
> Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
> ---
> gcc/gcse.cc | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/gcc/gcse.cc b/gcc/gcse.cc
> index 96aae0e1718..6eddffcdba8 100644
> --- a/gcc/gcse.cc
> +++ b/gcc/gcse.cc
> @@ -4238,8 +4238,15 @@ execute_hardreg_pre (void)
> {
> int changed;
> current_hardreg_regno = regnos[i];
> + if (!df_regs_ever_live_p (current_hardreg_regno))
> + {
> + if (dump_file)
> + fprintf (dump_file, "Skipping hardreg PRE for regno %d never
> alive\n",
How about: "Skipping hardreg PRE for regno %d, which is never live\n"
OK with that change, thanks.
Richard
> + current_hardreg_regno);
> + continue;
> + }
> if (dump_file)
> - fprintf(dump_file, "Entering hardreg PRE for regno %d\n",
> + fprintf (dump_file, "Entering hardreg PRE for regno %d\n",
> current_hardreg_regno);
> delete_unreachable_blocks ();
> df_analyze ();
