Changeset 27416 in webkit for trunk/JavaScriptCore/kjs/JSImmediate.h

Timestamp:

Nov 3, 2007, 8:37:21 PM (18 years ago)

Author:

mjs

Message:

Reviewed by Sam.

• remove NaN check from JSImmediate::fromDouble for 0.5% SunSpider speedup

It turns out that doing this check costs more than it saves.

• kjs/JSImmediate.h: (KJS::JSImmediate::fromDouble):

File:

• trunk/JavaScriptCore/kjs/JSImmediate.h (modified) (1 diff)

trunk/JavaScriptCore/kjs/JSImmediate.h

@@ -156 +156 @@
             return 0;
 
-        // check for data loss from conversion to float
-        // The d == d check is to allow NaN - it does not
-        // compare equal to itself, but we do want to allow it
-        if (floatUnion.asFloat != d && d == d)
-            return 0;
-
-        return tag(floatUnion.asBits, NumberType);
+        // check for data loss from conversion to float. This
+        // unfortunately also rejects NaN, however, it costs more to
+        // do a check that will include NaN than is saved by letting
+        // NaN be an immediate.
+        if (floatUnion.asFloat == d)
+            return tag(floatUnion.asBits, NumberType);
+
+        return 0;
     }