From: Kyrylo Tkachov <[email protected]>
noce_convert_multiple_sets_1 walks a candidate sequence twice looking for an
insn that clobbers the non-canonicalized condition, once for the sequence
built with it and once for the sequence built without. Both walks repeat the
same test, including the guard for rev_cc_cmp being absent.
Move it into noce_seq_clobbers_cc_cmp_p. No functional change.
gcc/ChangeLog:
* ifcvt.cc (noce_seq_clobbers_cc_cmp_p): New function.
(noce_convert_multiple_sets_1): Use it for both candidate sequences.
Signed-off-by: Kyrylo Tkachov <[email protected]>
---
gcc/ifcvt.cc | 42 +++++++++++++++++++++++-------------------
1 file changed, 23 insertions(+), 19 deletions(-)
diff --git a/gcc/ifcvt.cc b/gcc/ifcvt.cc
index cc485cb691b..c3beeaebe77 100644
--- a/gcc/ifcvt.cc
+++ b/gcc/ifcvt.cc
@@ -4241,6 +4241,20 @@ noce_convert_multiple_sets (struct noce_if_info *if_info)
return true;
}
+/* Return true if any insn in SEQ modifies CC_CMP, or REV_CC_CMP when there is
+ one. Such a sequence cannot be used to select on that condition. */
+
+static bool
+noce_seq_clobbers_cc_cmp_p (rtx_insn *seq, rtx cc_cmp, rtx rev_cc_cmp)
+{
+ for (rtx_insn *insn = seq; insn; insn = NEXT_INSN (insn))
+ if (modified_in_p (cc_cmp, insn)
+ || (rev_cc_cmp && modified_in_p (rev_cc_cmp, insn)))
+ return true;
+
+ return false;
+}
+
/* Try to emit the multiple-set conversion described by IF_INFO, selecting on
the already decoded jump condition COND. INSN_INFO holds THEN_COUNT
then-arm entries followed by entries for the else-only definitions recorded
@@ -4459,13 +4473,8 @@ noce_convert_multiple_sets_1 (noce_if_info *if_info, rtx
cond,
/* The if_then_else in SEQ2 may be affected when cc_cmp/rev_cc_cmp is
clobbered. We can't safely use the sequence in this case. */
- for (rtx_insn *iter = seq2; iter; iter = NEXT_INSN (iter))
- if (modified_in_p (cc_cmp, iter)
- || (rev_cc_cmp && modified_in_p (rev_cc_cmp, iter)))
- {
- seq2 = NULL;
- break;
- }
+ if (noce_seq_clobbers_cc_cmp_p (seq2, cc_cmp, rev_cc_cmp))
+ seq2 = NULL;
}
/* The backend might have created a sequence that uses the
@@ -4558,19 +4567,14 @@ noce_convert_multiple_sets_1 (noce_if_info *if_info,
rtx cond,
return false;
}
- if (cc_cmp && seq == seq1)
+ /* If SEQ clobbers registers mentioned in cc_cmp/rev_cc_cmp we have to
+ fall back on SEQ1 from that point on. Only check when we use SEQ1,
+ since SEQ2 has been tested already. */
+ if (cc_cmp && seq == seq1
+ && noce_seq_clobbers_cc_cmp_p (seq, cc_cmp, rev_cc_cmp))
{
- /* Check if SEQ can clobber registers mentioned in cc_cmp/rev_cc_cmp.
- If yes, we need to use only SEQ1 from that point on.
- Only check when we use SEQ1 since we have already tested SEQ2. */
- for (rtx_insn *iter = seq; iter; iter = NEXT_INSN (iter))
- if (modified_in_p (cc_cmp, iter)
- || (rev_cc_cmp && modified_in_p (rev_cc_cmp, iter)))
- {
- cc_cmp = NULL_RTX;
- rev_cc_cmp = NULL_RTX;
- break;
- }
+ cc_cmp = NULL_RTX;
+ rev_cc_cmp = NULL_RTX;
}
/* End the sub sequence and emit to the main sequence. */
--
2.50.1 (Apple Git-155)
