Enable the early scheduler on AArch64 for O3/Ofast. This means GCC15 benefits
from much faster build times with -O2, but avoids the regressions in lbm which
is very sensitive to minor scheduling changes due to long FMA chains. We can
then revisit this for GCC16.
gcc:
PR target/118351
* common/config/aarch64/aarch64-common.cc: Enable early scheduling with
-O3 and higher.
---
diff --git a/gcc/common/config/aarch64/aarch64-common.cc
b/gcc/common/config/aarch64/aarch64-common.cc
index
3d694f16d1fd84e142254a4880c91a7f053e72aa..3044336923415d9414b6c66e66d872612ead24cd
100644
--- a/gcc/common/config/aarch64/aarch64-common.cc
+++ b/gcc/common/config/aarch64/aarch64-common.cc
@@ -54,8 +54,10 @@ static const struct default_options
aarch_option_optimization_table[] =
{ OPT_LEVELS_FAST, OPT_fomit_frame_pointer, NULL, 1 },
/* Enable -fsched-pressure by default when optimizing. */
{ OPT_LEVELS_1_PLUS, OPT_fsched_pressure, NULL, 1 },
- /* Disable early scheduling due to high compile-time overheads. */
+ /* Except for -O3 and higher, disable early scheduling due to high
+ compile-time overheads. */
{ OPT_LEVELS_ALL, OPT_fschedule_insns, NULL, 0 },
+ { OPT_LEVELS_3_PLUS, OPT_fschedule_insns, NULL, 1 },
/* Enable redundant extension instructions removal at -O2 and higher. */
{ OPT_LEVELS_2_PLUS, OPT_free, NULL, 1 },
{ OPT_LEVELS_2_PLUS, OPT_mearly_ra_, NULL, AARCH64_EARLY_RA_ALL },
