Changeset 149013 in webkit

Timestamp:

Apr 23, 2013 6:10:51 PM (11 years ago)

Author:

akling@apple.com

Message:

Micro-optimize Length::initFromLength().
<​http://webkit.org/b/115073>

From Blink r148621 by <​timloh@chromium.org>:

This appears to improve html5-full-render by 1-2% on my system (gcc 4.6.3) by using memcpy
instead of copying members (and branching to copy the union).

• platform/Length.h:

(WebCore::Length::initFromLength):

Location:

trunk/Source/WebCore

Files:

• ChangeLog (modified) (1 diff)
• platform/Length.h (modified) (2 diffs)

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2013-04-23  Andreas Kling  <akling@apple.com>
+
+        Micro-optimize Length::initFromLength().
+        <http://webkit.org/b/115073>
+
+        From Blink r148621 by <timloh@chromium.org>:
+
+        This appears to improve html5-full-render by 1-2% on my system (gcc 4.6.3) by using memcpy
+        instead of copying members (and branching to copy the union).
+
+        * platform/Length.h:
+        (WebCore::Length::initFromLength):
+
 2013-04-23  Kent Tamura  <tkent@chromium.org>
 

trunk/Source/WebCore/platform/Length.h

@@ -25 +25 @@
 
 #include "AnimationUtilities.h"
+#include <string.h>
 #include <wtf/Assertions.h>
 #include <wtf/FastAllocBase.h>
@@ -280 +281 @@
         return m_isFloat ? static_cast<int>(m_floatValue) : m_intValue;
     }
-    void initFromLength(const Length &length) 
-    {
-        m_quirk = length.m_quirk;
-        m_type = length.m_type;
-        m_isFloat = length.m_isFloat;
-        
-        if (m_isFloat)
-            m_floatValue = length.m_floatValue;
-        else
-            m_intValue = length.m_intValue;
-        
+    void initFromLength(const Length& length)
+    {
+        memcpy(this, &length, sizeof(Length));
         if (isCalculated())
             incrementCalculatedRef();