diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 15e3633814f0..169ee51a5847 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,4 +1,7 @@
-2000-05-13  Geoffrey Keating  <geoffk@cygnus.com>
+2000-05-14  Geoffrey Keating  <geoffk@cygnus.com>
+
+	* optabs.c (expand_float): Don't allow mode widening that causes
+	double rounding.
 
 	* invoke.texi (RS/6000 and PowerPC Options): Update -m64/-m32
 	flags to their current names -maix64 and -maix32.
diff --git a/gcc/optabs.c b/gcc/optabs.c
index 0cfe0649d6fc..9f9871581aa6 100644
--- a/gcc/optabs.c
+++ b/gcc/optabs.c
@@ -3888,6 +3888,10 @@ expand_float (to, from, unsignedp)
       {
 	int doing_unsigned = unsignedp;
 
+	if (fmode != GET_MODE (to)
+	    && significand_size (fmode) < GET_MODE_BITSIZE (GET_MODE (from)))
+	  continue;
+
 	icode = can_float_p (fmode, imode, unsignedp);
 	if (icode == CODE_FOR_nothing && imode != GET_MODE (from) && unsignedp)
 	  icode = can_float_p (fmode, imode, 0), doing_unsigned = 0;