xtensa: Turn on -fsplit-wide-types-early by default
Commit Message
Since GCC10, the "subreg2" optimization pass was no longer tied to enabling
"subreg1" unless -fsplit-wide-types-early was turned on (PR88233). However
on the Xtensa port, the lack of "subreg2" can degrade the quality of the
output code, especially for those that produce many D[FC]mode pseudos.
This patch turns on -fsplit-wide-types-early by default in order to restore
the previous behavior.
gcc/ChangeLog:
* common/config/xtensa/xtensa-common.cc
(xtensa_option_optimization_table): Add OPT_fsplit_wide_types_early
for OPT_LEVELS_ALL in order to restore pre-GCC10 behavior.
---
gcc/common/config/xtensa/xtensa-common.cc | 2 ++
1 file changed, 2 insertions(+)
Comments
On Sun, Aug 14, 2022 at 2:31 AM Takayuki 'January June' Suwa
<jjsuwa_sys3175@yahoo.co.jp> wrote:
>
> Since GCC10, the "subreg2" optimization pass was no longer tied to enabling
> "subreg1" unless -fsplit-wide-types-early was turned on (PR88233). However
> on the Xtensa port, the lack of "subreg2" can degrade the quality of the
> output code, especially for those that produce many D[FC]mode pseudos.
>
> This patch turns on -fsplit-wide-types-early by default in order to restore
> the previous behavior.
>
> gcc/ChangeLog:
>
> * common/config/xtensa/xtensa-common.cc
> (xtensa_option_optimization_table): Add OPT_fsplit_wide_types_early
> for OPT_LEVELS_ALL in order to restore pre-GCC10 behavior.
> ---
> gcc/common/config/xtensa/xtensa-common.cc | 2 ++
> 1 file changed, 2 insertions(+)
Regtested for target=xtensa-linux-uclibc, no new regressions.
Committed to master.
@@ -34,6 +34,8 @@ static const struct default_options xtensa_option_optimization_table[] =
assembler, so GCC cannot do a good job of reordering blocks.
Do not enable reordering unless it is explicitly requested. */
{ OPT_LEVELS_ALL, OPT_freorder_blocks, NULL, 0 },
+ /* Split multi-word types early (pre-GCC10 behavior). */
+ { OPT_LEVELS_ALL, OPT_fsplit_wide_types_early, NULL, 1 },
{ OPT_LEVELS_NONE, 0, NULL, 0 }
};