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reorg.c (relax_delay_slots): When optimizing for code size... 

* reorg.c (relax_delay_slots): When optimizing for code size, if a
        return with a filled delay slot is followed by a return with an
        unfilled delay slot, delete the first return and reemit the insn
        that was previously in its delay slot.

From-SVN: r23729
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Jeffrey A Law 1998-11-19 22:45:14 +00:00 committed by Jeff Law
parent e9741ffa97
commit 9f5a2691a1
2 changed files with 39 additions and 0 deletions
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5
gcc/ChangeLog
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@ -1,5 +1,10 @@
Thu Nov 19 22:20:51 1998 Jeffrey A Law (law@cygnus.com)
* reorg.c (relax_delay_slots): When optimizing for code size, if a
return with a filled delay slot is followed by a return with an
unfilled delay slot, delete the first return and reemit the insn
that was previously in its delay slot.
* i860.c (single_insn_src_p): Add missing parens.
* ginclude/math-3300.h: Likewise.

34
gcc/reorg.c
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@ -4200,6 +4200,40 @@ relax_delay_slots (first)
continue;
}
/* See if we have a RETURN insn with a filled delay slot followed
by a RETURN insn with an unfilled a delay slot. If so, we can delete
the first RETURN (but not it's delay insn). This gives the same
effect in fewer instructions.
Only do so if optimizing for size since this results in slower, but
smaller code. */
if (optimize_size
&& GET_CODE (PATTERN (delay_insn)) == RETURN
&& next
&& GET_CODE (next) == JUMP_INSN
&& GET_CODE (PATTERN (next)) == RETURN)
{
int i;
/* Delete the RETURN and just execute the delay list insns.
We do this by deleting the INSN containing the SEQUENCE, then
re-emitting the insns separately, and then deleting the RETURN.
This allows the count of the jump target to be properly
decremented. */
/* Clear the from target bit, since these insns are no longer
in delay slots. */
for (i = 0; i < XVECLEN (pat, 0); i++)
INSN_FROM_TARGET_P (XVECEXP (pat, 0, i)) = 0;
trial = PREV_INSN (insn);
delete_insn (insn);
emit_insn_after (pat, trial);
delete_scheduled_jump (delay_insn);
continue;
}
/* Now look only at the cases where we have a filled JUMP_INSN. */
if (GET_CODE (XVECEXP (PATTERN (insn), 0, 0)) != JUMP_INSN
|| ! (condjump_p (XVECEXP (PATTERN (insn), 0, 0))