http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60580
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jakub at gcc dot gnu.org,
| |jsm28 at gcc dot gnu.org,
| |uros at gcc dot gnu.org
--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
This is a complete mess, what aarch64 backend does is completely incompatible
with optimize attribute. I've tried to fix this up:
--- gcc/config/aarch64/aarch64.opt.jj 2014-01-20 14:50:22.000000000 +0100
+++ gcc/config/aarch64/aarch64.opt 2014-03-19 11:52:29.963772607 +0100
@@ -59,6 +59,11 @@ const char *aarch64_cpu_string
Variable
const char *aarch64_tune_string
+; Did we set flag_omit_frame_pointer just so aarch64_frame_pointer_required
+; would be called?
+Variable
+bool faked_omit_frame_pointer
+
mbig-endian
Target Report RejectNegative Mask(BIG_END)
Assume target CPU is configured as big endian
--- gcc/config/aarch64/aarch64.c.jj 2014-03-18 12:26:13.000000000 +0100
+++ gcc/config/aarch64/aarch64.c 2014-03-19 12:20:19.471504562 +0100
@@ -315,10 +315,6 @@ static GTY(()) int gty_dummy;
#define AARCH64_NUM_BITMASKS 5334
static unsigned HOST_WIDE_INT aarch64_bitmasks[AARCH64_NUM_BITMASKS];
-/* Did we set flag_omit_frame_pointer just so
- aarch64_frame_pointer_required would be called? */
-static bool faked_omit_frame_pointer;
-
typedef enum aarch64_cond_code
{
AARCH64_EQ = 0, AARCH64_NE, AARCH64_CS, AARCH64_CC, AARCH64_MI, AARCH64_PL,
@@ -5278,7 +5274,11 @@ aarch64_override_options (void)
static void
aarch64_override_options_after_change (void)
{
- faked_omit_frame_pointer = false;
+ if (global_options_set.x_flag_omit_frame_pointer)
+ {
+ faked_omit_frame_pointer = false;
+ global_options_set.x_faked_omit_frame_pointer = false;
+ }
/* To omit leaf frame pointers, we need to turn flag_omit_frame_pointer on
so
that aarch64_frame_pointer_required will be called. We need to remember
@@ -5288,6 +5288,9 @@ aarch64_override_options_after_change (v
{
flag_omit_frame_pointer = true;
faked_omit_frame_pointer = true;
+ global_options_set.x_faked_omit_frame_pointer
+ = global_options_set.x_flag_omit_frame_pointer;
+ global_options_set.x_flag_omit_frame_pointer = false;
}
}
but while that fixes some of the cases, it doesn't fix everything, the problem
is that the non-TargetVariable Variables aren't actually Saved.
Now, i386 backend seems to handle it differently, instead of adding a
faked_omit_frame_pointer variable (which, as this PR suggests would need to be
handled as an Optimization Saved variable, but supposedly the opts framework
doesn't allow it yet), it clears omit_leaf_frame_pointer flag if
flag_omit_frame_pointer is true:
/* Keep nonleaf frame pointers. */
if (opts->x_flag_omit_frame_pointer)
opts->x_target_flags &= ~MASK_OMIT_LEAF_FRAME_POINTER;
else if (TARGET_OMIT_LEAF_FRAME_POINTER_P (opts->x_target_flags))
opts->x_flag_omit_frame_pointer = 1;
but does that only in in override_options hook. That means that
say for -fomit-frame-pointer -momit-leaf-frame-pointer on the command line
supposedly that turns off TARGET_OMIT_LEAF_FRAME_POINTER and when some function
has __attribute__((optimize ("no-omit-frame-pointer"))) and is leaf, frame
pointer will not be omitted there. But for -fno-omit-frame-pointer
-momit-leaf-frame-pointer on the command line and __attribute__((optimize
("no-omit-frame-pointer"))) supposedly it will not have frame pointer if it is
leaf.
The primary issue is that flag_omit_frame_pointer is Optimization Save flag,
while omit-leaf-frame-pointer is typcially Target Save, the former optimize
attribute thing, the latter target attribute thing.
Not sure what is the best way out of this, but I guess doing in aarch64 what
i386 does would be significant progress.
