diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 13aa77851de..d1ce533a02c 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -4,6 +4,8 @@
 	(determine_max_iter): Take additional LOOP arg; all callers changed.
 	Lose broken logic dealing with PLUS.  Try to limit the upper bound by
 	one using simplifications.
+	(simplify_using_initial_values): Return if the expression becomes
+	invalid due to altered regs.
 
 2007-02-23  DJ Delorie  <dj@redhat.com>
 
diff --git a/gcc/loop-iv.c b/gcc/loop-iv.c
index fb0ec4525cc..21005d3ff51 100644
--- a/gcc/loop-iv.c
+++ b/gcc/loop-iv.c
@@ -1811,6 +1811,8 @@ simplify_using_initial_values (struct loop *loop, enum rtx_code op, rtx *expr)
 	      FREE_REG_SET (altered);
 	      return;
 	    }
+	  if (for_each_rtx (expr, altered_reg_used, altered))
+	    return;
 	}
 
       if (!single_pred_p (e->src)