Delayed slot filling moves insns without any regard to variable
location notes, causing the location information in them to become
incorrect.
Fixing that appears to be quite difficult, but filling delay slots is
hardly an essential optimization to run at -Og, so if the user wants
to privilege debuggability, skip delay slot filling.
Regstrapped on sparc64-, x86- and x86_64-linux-gnu. Also bootstrapped
on sparc64-linux-gnu with BOOT_CFLAGS='-Og -g' (needed
-Wno-error={{maybe-,}uninitialized,format-overflow}))
Ok to install?
for gcc/ChangeLog
* opts.c (default_options_table): Do not enable
OPT_fdelayed_branch at -Og.
* doc/invoke.texi (-fdelayed-branch): Document it.
---
gcc/doc/invoke.texi | 3 ++-
gcc/opts.c | 2 +-
2 files changed, 3 insertions(+), 2 deletions(-)
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index 57491f1033cf..052a0999a590 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -8585,7 +8585,8 @@ If supported for the target machine, attempt to reorder
instructions
to exploit instruction slots available after delayed branch
instructions.
-Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os}.
+Enabled at levels @option{-O}, @option{-O2}, @option{-O3}, @option{-Os},
+but not at @option{-Og}.
@item -fschedule-insns
@opindex fschedule-insns
diff --git a/gcc/opts.c b/gcc/opts.c
index 3b61e17a7ab0..34c283dd7655 100644
--- a/gcc/opts.c
+++ b/gcc/opts.c
@@ -442,7 +442,7 @@ static const struct default_options default_options_table[]
=
/* -O1 optimizations. */
{ OPT_LEVELS_1_PLUS, OPT_fdefer_pop, NULL, 1 },
#if DELAY_SLOTS
- { OPT_LEVELS_1_PLUS, OPT_fdelayed_branch, NULL, 1 },
+ { OPT_LEVELS_1_PLUS_NOT_DEBUG, OPT_fdelayed_branch, NULL, 1 },
#endif
{ OPT_LEVELS_1_PLUS, OPT_fguess_branch_probability, NULL, 1 },
{ OPT_LEVELS_1_PLUS, OPT_fcprop_registers, NULL, 1 },
--
Alexandre Oliva, freedom fighter https://FSFLA.org/blogs/lxo
Be the change, be Free! FSF Latin America board member
GNU Toolchain Engineer Free Software Evangelist
Hay que enGNUrecerse, pero sin perder la terGNUra jamás-GNUChe
