Index: optabs.c
===================================================================
--- optabs.c    (revision 193394)
+++ optabs.c    (working copy)
@@ -170,9 +170,9 @@ optab_libfunc (optab optab, enum machine

    If the last insn does not set TARGET, don't do anything, but return 1.

-   If a previous insn sets TARGET and TARGET is one of OP0 or OP1,
-   don't add the REG_EQUAL note but return 0.  Our caller can then try
-   again, ensuring that TARGET is not one of the operands.  */
+   If the last insn or a previous insn sets TARGET and TARGET is one of OP0
+   or OP1, don't add the REG_EQUAL note but return 0.  Our caller can then
+   try again, ensuring that TARGET is not one of the operands.  */

 static int
 add_equal_note (rtx insns, rtx target, enum rtx_code code, rtx op0, rtx op1)
@@ -192,6 +192,12 @@ add_equal_note (rtx insns, rtx target, e
   if (GET_CODE (target) == ZERO_EXTRACT)
     return 1;

+  /* If TARGET is in OP0 or OP1, punt.  We'd end up with a note referencing
+     a value changing in the insn, so the note would be invalid for CSE.  */
+  if (reg_overlap_mentioned_p (target, op0)
+      || (op1 && reg_overlap_mentioned_p (target, op1)))
+    return 0;
+
   for (last_insn = insns;
        NEXT_INSN (last_insn) != NULL_RTX;
        last_insn = NEXT_INSN (last_insn))
@@ -207,21 +213,6 @@ add_equal_note (rtx insns, rtx target, e
          || ! rtx_equal_p (XEXP (SET_DEST (set), 0), target)))
     return 1;

-  /* If TARGET is in OP0 or OP1, check if anything in SEQ sets TARGET
-     besides the last insn.  */
-  if (reg_overlap_mentioned_p (target, op0)
-      || (op1 && reg_overlap_mentioned_p (target, op1)))
-    {
-      insn = PREV_INSN (last_insn);
-      while (insn != NULL_RTX)
-       {
-         if (reg_set_p (target, insn))
-           return 0;
-
-         insn = PREV_INSN (insn);
-       }
-    }
-
   if (GET_RTX_CLASS (code) == RTX_UNARY)
     switch (code)
       {