On 10/05/11 17:13, Richard Guenther wrote:
> On Wed, Oct 5, 2011 at 12:29 AM, Richard Henderson <[email protected]> wrote:
>> On 10/04/2011 03:10 PM, Bernd Schmidt wrote:
>>> * doc/invoke.texi (-fshrink-wrap): Document.
>>> * opts.c (default_options_table): Add it.
>>> * common.opt (fshrink-wrap): Add.
>>> * function.c (emit_return_into_block): Remove useless declaration.
>>> (record_hard_reg_uses_1, record_hard_reg_uses, frame_required_for_rtx,
>>> requires_stack_frame_p, gen_return_pattern): New static functions.
>>> (emit_return_into_block): New arg simple_p. All callers changed.
>>> Use gen_return_pattern.
>>> (thread_prologue_and_epilogue_insns): Implement shrink-wrapping.
>>> * config/i386/i386.md (return): Expand into a simple_return.
>>> (simple_return): New expander):
>>> (simple_return_internal, simple_return_internal_long,
>>> simple_return_pop_internal_long, simple_return_indirect_internal):
>>> Renamed from return_internal, return_internal_long,
>>> return_pop_internal_long and return_indirect_internal; changed to use
>>> simple_return.
>>> * config/i386/i386.c (ix86_expand_epilogue): Adjust to expand
>>> simple returns.
>>> (ix86_pad_returns): Likewise.
>>> * function.h (struct rtl_data): Add member shrink_wrapped.
>>> * cfgcleanup.c (outgoing_edges_match): If shrink-wrapped, edges that
>>> are not jumps or sibcalls can't be compared.
>>>
>>> * gcc.target/i386/sw-1.c: New test.
>>
>> Ok.
>>
>> As a followup, I think this option needs to be disabled for profiling
>> and profile_after_prologue. Should be a mere matter of frobbing the
>> options at startup.
>
> This breaks bootstrap on x86_64-linux.
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50621
Caused by the x86_64 expand_epilogue not generating REG_CFA_RESTORE
notes, and in another case by queuing but not emitting them.
Bootstrapping the following now. Ok? (Alternatively, could keep the
redzone logic, but make it depend on !flag_shrink_wrap).
Bernd
* config/i386/i386.c (ix86_add_cfa_restore_note): Lose CFA_OFFSET
argument. All callers changed. Always emit a note.
(ix86_expand_epilogue): Ensure queued cfa_adjust notes are attached
to an insn.
Index: gcc/config/i386/i386.c
===================================================================
--- gcc/config/i386/i386.c (revision 179553)
+++ gcc/config/i386/i386.c (working copy)
@@ -9126,17 +9126,11 @@ ix86_emit_save_sse_regs_using_mov (HOST_
static GTY(()) rtx queued_cfa_restores;
/* Add a REG_CFA_RESTORE REG note to INSN or queue them until next stack
- manipulation insn. The value is on the stack at CFA - CFA_OFFSET.
- Don't add the note if the previously saved value will be left untouched
- within stack red-zone till return, as unwinders can find the same value
- in the register and on the stack. */
+ manipulation insn. */
static void
-ix86_add_cfa_restore_note (rtx insn, rtx reg, HOST_WIDE_INT cfa_offset)
+ix86_add_cfa_restore_note (rtx insn, rtx reg)
{
- if (cfa_offset <= cfun->machine->fs.red_zone_offset)
- return;
-
if (insn)
{
add_reg_note (insn, REG_CFA_RESTORE, reg);
@@ -10298,7 +10292,7 @@ ix86_emit_restore_reg_using_pop (rtx reg
struct machine_function *m = cfun->machine;
rtx insn = emit_insn (gen_pop (reg));
- ix86_add_cfa_restore_note (insn, reg, m->fs.sp_offset);
+ ix86_add_cfa_restore_note (insn, reg);
m->fs.sp_offset -= UNITS_PER_WORD;
if (m->fs.cfa_reg == crtl->drap_reg
@@ -10383,8 +10377,7 @@ ix86_emit_leave (void)
add_reg_note (insn, REG_CFA_DEF_CFA,
plus_constant (stack_pointer_rtx, m->fs.sp_offset));
RTX_FRAME_RELATED_P (insn) = 1;
- ix86_add_cfa_restore_note (insn, hard_frame_pointer_rtx,
- m->fs.fp_offset);
+ ix86_add_cfa_restore_note (insn, hard_frame_pointer_rtx);
}
}
@@ -10421,7 +10414,7 @@ ix86_emit_restore_regs_using_mov (HOST_W
m->fs.drap_valid = true;
}
else
- ix86_add_cfa_restore_note (NULL_RTX, reg, cfa_offset);
+ ix86_add_cfa_restore_note (NULL_RTX, reg);
cfa_offset -= UNITS_PER_WORD;
}
@@ -10446,7 +10439,7 @@ ix86_emit_restore_sse_regs_using_mov (HO
set_mem_align (mem, 128);
emit_move_insn (reg, mem);
- ix86_add_cfa_restore_note (NULL_RTX, reg, cfa_offset);
+ ix86_add_cfa_restore_note (NULL_RTX, reg);
cfa_offset -= 16;
}
@@ -10738,6 +10731,8 @@ ix86_expand_epilogue (int style)
GEN_INT (m->fs.sp_offset - UNITS_PER_WORD),
style, true);
}
+ else
+ ix86_add_queued_cfa_restore_notes (get_last_insn ());
/* Sibcall epilogues don't want a return instruction. */
if (style == 0)
