From: Richard Stallman <rms@gnu.org>
Date: Tue, 16 Mar 1993 04:54:43 +0000 (+0000)
Subject: (expand_binop): For doubleword int addition,
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=af2cc4dd6953054b4a1d068dc5bffeeb6170f37b;p=gcc.git

(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 5229f9727a1..81b5f69d6fb 100644
--- 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++)
 	{