(expand_binop): For doubleword int addition,

clobber the whole register at the start.

From-SVN: r3754

diff --git a/gcc/optabs.c b/gcc/optabs.c
index 5229f9727a173ce7d864f8fbd3ed740abddf95e3..81b5f69d6fb89544203dd27efbde957af618e8c0 100644 (file)
--- a/gcc/optabs.c
+++ b/gcc/optabs.c
@@ -590,6 +590,10 @@ expand_binop (mode, binoptab, op0, op1, target, unsignedp, methods)
          || target == xop0 || target == xop1)
        target = gen_reg_rtx (mode);
 
+      /* Indicate for flow that the entire target reg is being set.  */
+      if (GET_CODE (target) == REG)
+       emit_insn (gen_rtx (CLOBBER, VOIDmode, target));
+
       /* Do the actual arithmetic.  */
       for (i = 0; i < nwords; i++)
        {