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combine.c (can_combine_p): Don't ignore SETs marked with REG_EH_REGION notes.

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* combine.c (can_combine_p): Don't ignore SETs marked with
	REG_EH_REGION notes.
	(try_combine): When attemting to fix unrecognized insns, don't
	split a PARALLEL that contains the original i2.

From-SVN: r78220
This commit is contained in:
Alan Modra 2004-02-21 13:03:40 +00:00 committed by Alan Modra
parent fe932e504b
commit da6fdad3bb
2 changed files with 24 additions and 4 deletions
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7
gcc/ChangeLog
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@ -1,3 +1,10 @@
2004-02-21 Alan Modra <amodra@bigpond.net.au>
* combine.c (can_combine_p): Don't ignore SETs marked with
REG_EH_REGION notes.
(try_combine): When attemting to fix unrecognized insns, don't
split a PARALLEL that contains the original i2.
2004-02-21 Ziemowit Laski <zlaski@apple.com>
* config/darwin.h (TARGET_OPTION_TRANSLATE_TABLE): Refer to

21
gcc/combine.c
View File

@ -960,6 +960,7 @@ can_combine_p (rtx insn, rtx i3, rtx pred ATTRIBUTE_UNUSED, rtx succ,
for (i = 0; i < XVECLEN (PATTERN (insn), 0); i++)
{
rtx elt = XVECEXP (PATTERN (insn), 0, i);
rtx note;
switch (GET_CODE (elt))
{
@ -1010,6 +1011,8 @@ can_combine_p (rtx insn, rtx i3, rtx pred ATTRIBUTE_UNUSED, rtx succ,
/* Ignore SETs whose result isn't used but not those that
have side-effects. */
if (find_reg_note (insn, REG_UNUSED, SET_DEST (elt))
&& (!(note = find_reg_note (insn, REG_EH_REGION, NULL_RTX))
|| INTVAL (XEXP (note, 0)) <= 0)
&& ! side_effects_p (elt))
break;
@ -2019,11 +2022,21 @@ try_combine (rtx i3, rtx i2, rtx i1, int *new_direct_jump_p)
we just need the first SET. This can occur when simplifying a divmod
insn. We *must* test for this case here because the code below that
splits two independent SETs doesn't handle this case correctly when it
updates the register status. Also check the case where the first
SET's destination is unused. That would not cause incorrect code, but
does cause an unneeded insn to remain. */
updates the register status.
if (insn_code_number < 0 && GET_CODE (newpat) == PARALLEL
It's pointless doing this if we originally had two sets, one from
i3, and one from i2. Combining then splitting the parallel results
in the original i2 again plus an invalid insn (which we delete).
The net effect is only to move instructions around, which makes
debug info less accurate.
Also check the case where the first SET's destination is unused.
That would not cause incorrect code, but does cause an unneeded
insn to remain. */
if (insn_code_number < 0
&& !(added_sets_2 && i1 == 0)
&& GET_CODE (newpat) == PARALLEL
&& XVECLEN (newpat, 0) == 2
&& GET_CODE (XVECEXP (newpat, 0, 0)) == SET
&& GET_CODE (XVECEXP (newpat, 0, 1)) == SET