diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 96de8a0569077887f14e8620387251ef6ddcb2c3..d1930ad7ceea901438c79cca55dfefd59226e7a9 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2008-06-04  Andy Hutchinson  <hutchinsonandy@aim.com>
+
+	PR target/30243
+	* builtins.c (expand_builtin_signbit): Don't take lowpart when
+	register is already smaller or equal to required mode. 
+
 2008-06-04  Xinliang David Li  <davidxl@google.com>
 
 	* tree-call-cdce.c: New file. 
diff --git a/gcc/builtins.c b/gcc/builtins.c
index 05eb6bbdd985c975a6303e8b2d1093fb36c22bbb..f2c6ed488af15f8e3f288b7530d1d21dc0d15c46 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -5786,7 +5786,7 @@ expand_builtin_signbit (tree exp, rtx target)
 	  lo = 0;
 	}
 
-      if (imode != rmode)
+      if (GET_MODE_SIZE (imode) > GET_MODE_SIZE (rmode))
 	temp = gen_lowpart (rmode, temp);
       temp = expand_binop (rmode, and_optab, temp,
 			   immed_double_const (lo, hi, rmode),