diff --git a/ChangeLog b/ChangeLog
index 82aa55bfd3..8fc49c8f9c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Mon Sep  3 21:22:37 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* include/ruby/ruby.h (rb_float_value): suppress warnings.
+	  [ruby-core:47406][Bug #6971]
+
 Mon Sep  3 14:49:03 2012  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* lib/matrix.rb (Vector#magnitude): accumulate squares of absolute
diff --git a/include/ruby/ruby.h b/include/ruby/ruby.h
index b8b2267006..a674de8dc6 100644
--- a/include/ruby/ruby.h
+++ b/include/ruby/ruby.h
@@ -743,7 +743,7 @@ rb_float_value(VALUE v)
 	    /* e: xx1... -> 011... */
 	    /*    xx0... -> 100... */
 	    /*      ^b63           */
-	    t.v = RUBY_BIT_ROTR(2 - b63 | (v & ~0x03), 3);
+	    t.v = RUBY_BIT_ROTR((2 - b63) | (v & ~0x03), 3);
 	    return t.d;
 	}
 	else {