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re PR target/46470 ("add $0x8,%rsp" no longer optimized to pop)

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PR target/46470
        * recog.c (peep2_attempt): Convert frame-related info when possible.
        (peep2_fill_buffer): Allow frame-related insns into the buffer.
        (peephole2_optimize): Allow peep2_attempt to fail.

From-SVN: r166829
This commit is contained in:
Richard Henderson 2010-11-16 14:22:13 -08:00 committed by Richard Henderson
parent 885c9b5d3a
commit cfc76ec4d0
3 changed files with 108 additions and 18 deletions
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7
gcc/ChangeLog
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@ -1,3 +1,10 @@
2010-11-16 Richard Henderson <rth@redhat.com>
PR target/46470
* recog.c (peep2_attempt): Convert frame-related info when possible.
(peep2_fill_buffer): Allow frame-related insns into the buffer.
(peephole2_optimize): Allow peep2_attempt to fail.
2010-11-16 Eric Botcazou <ebotcazou@adacore.com>
PR rtl-optimization/46315

110
gcc/recog.c
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@ -3134,22 +3134,99 @@ peep2_reinit_state (regset live)
/* While scanning basic block BB, we found a match of length MATCH_LEN,
starting at INSN. Perform the replacement, removing the old insns and
replacing them with ATTEMPT. Returns the last insn emitted. */
replacing them with ATTEMPT. Returns the last insn emitted, or NULL
if the replacement is rejected. */
static rtx
peep2_attempt (basic_block bb, rtx insn, int match_len, rtx attempt)
{
int i;
rtx last, note, before_try, x;
rtx old_insn, new_insn;
bool was_call = false;
/* If we are splittind an RTX_FRAME_RELATED_P insn, do not allow it to
match more than one insn, or to be split into more than one insn. */
old_insn = peep2_insn_data[peep2_current].insn;
if (RTX_FRAME_RELATED_P (old_insn))
{
bool any_note = false;
if (match_len != 0)
return NULL;
/* Look for one "active" insn. I.e. ignore any "clobber" insns that
may be in the stream for the purpose of register allocation. */
if (active_insn_p (attempt))
new_insn = attempt;
else
new_insn = next_active_insn (attempt);
if (next_active_insn (new_insn))
return NULL;
/* We have a 1-1 replacement. Copy over any frame-related info. */
RTX_FRAME_RELATED_P (new_insn) = 1;
/* Allow the backend to fill in a note during the split. */
for (note = REG_NOTES (new_insn); note ; note = XEXP (note, 1))
switch (REG_NOTE_KIND (note))
{
case REG_FRAME_RELATED_EXPR:
case REG_CFA_DEF_CFA:
case REG_CFA_ADJUST_CFA:
case REG_CFA_OFFSET:
case REG_CFA_REGISTER:
case REG_CFA_EXPRESSION:
case REG_CFA_RESTORE:
case REG_CFA_SET_VDRAP:
any_note = true;
break;
default:
break;
}
/* If the backend didn't supply a note, copy one over. */
if (!any_note)
for (note = REG_NOTES (old_insn); note ; note = XEXP (note, 1))
switch (REG_NOTE_KIND (note))
{
case REG_FRAME_RELATED_EXPR:
case REG_CFA_DEF_CFA:
case REG_CFA_ADJUST_CFA:
case REG_CFA_OFFSET:
case REG_CFA_REGISTER:
case REG_CFA_EXPRESSION:
case REG_CFA_RESTORE:
case REG_CFA_SET_VDRAP:
add_reg_note (new_insn, REG_NOTE_KIND (note), XEXP (note, 0));
any_note = true;
break;
default:
break;
}
/* If there still isn't a note, make sure the unwind info sees the
same expression as before the split. */
if (!any_note)
{
rtx old_set, new_set;
/* The old insn had better have been simple, or annotated. */
old_set = single_set (old_insn);
gcc_assert (old_set != NULL);
new_set = single_set (new_insn);
if (!new_set || !rtx_equal_p (new_set, old_set))
add_reg_note (new_insn, REG_FRAME_RELATED_EXPR, old_set);
}
}
/* If we are splitting a CALL_INSN, look for the CALL_INSN
in SEQ and copy our CALL_INSN_FUNCTION_USAGE and other
cfg-related call notes. */
for (i = 0; i <= match_len; ++i)
{
int j;
rtx old_insn, new_insn, note;
j = peep2_buf_position (peep2_current + i);
old_insn = peep2_insn_data[j].insn;
@ -3322,18 +3399,14 @@ peep2_fill_buffer (basic_block bb, rtx insn, regset live)
if (peep2_current_count == MAX_INSNS_PER_PEEP2)
return false;
/* If an insn has RTX_FRAME_RELATED_P set, peephole substitution would lose
the REG_FRAME_RELATED_EXPR that is attached. */
/* If an insn has RTX_FRAME_RELATED_P set, do not allow it to be matched with
any other pattern, lest it change the semantics of the frame info. */
if (RTX_FRAME_RELATED_P (insn))
{
/* Let the buffer drain first. */
if (peep2_current_count > 0)
return false;
/* Step over the insn then return true without adding the insn
to the buffer; this will cause us to process the next
insn. */
df_simulate_one_insn_forwards (bb, insn, live);
return true;
/* Now the insn will be the only thing in the buffer. */
}
pos = peep2_buf_position (peep2_current + peep2_current_count);
@ -3412,16 +3485,17 @@ peephole2_optimize (void)
attempt = peephole2_insns (PATTERN (head), head, &match_len);
if (attempt != NULL)
{
rtx last;
last = peep2_attempt (bb, head, match_len, attempt);
peep2_update_life (bb, match_len, last, PREV_INSN (attempt));
}
else
{
/* If no match, advance the buffer by one insn. */
peep2_current = peep2_buf_position (peep2_current + 1);
peep2_current_count--;
rtx last = peep2_attempt (bb, head, match_len, attempt);
if (last)
{
peep2_update_life (bb, match_len, last, PREV_INSN (attempt));
continue;
}
}
/* No match: advance the buffer by one insn. */
peep2_current = peep2_buf_position (peep2_current + 1);
peep2_current_count--;
}
}

9
gcc/testsuite/gcc.target/i386/pr46470.c Normal file
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@ -0,0 +1,9 @@
/* { dg-do compile } */
/* { dg-options "-Os -fomit-frame-pointer -fasynchronous-unwind-tables" } */
/* { dg-options "-Os -fomit-frame-pointer -mpreferred-stack-boundary=3 -fasynchronous-unwind-tables" { target ilp32 } } */
void f();
void g() { f(); f(); }
/* Both stack allocate and deallocate should be converted to push/pop. */
/* { dg-final { scan-assembler-not "sp" } } */