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(+)
diff --git a/gcc/common/config/xtensa/xtensa-common.cc
b/gcc/common/config/xtensa/xtensa-common.cc
index fbbe9b0aad7..0f27763aa71 100644
--- a/gcc/common/config/xtensa/xtensa-common.cc
+++ b/gcc/common/config/xtensa/xtensa-common.cc
@@ -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 }
};
--
2.20.1
