Performance related change, Optimization for / and % operator.

Source/platform/fonts/SimpleFontData.cpp

Index: Source/platform/fonts/SimpleFontData.cpp
diff --git a/Source/platform/fonts/SimpleFontData.cpp b/Source/platform/fonts/SimpleFontData.cpp
index da13c13985b10d54f2ae08a6f0b9b2a019ead071..e358899123dbe87c480fe1fd27dcd87364d79326 100644
--- a/Source/platform/fonts/SimpleFontData.cpp
+++ b/Source/platform/fonts/SimpleFontData.cpp
@@ -160,8 +160,10 @@ const SimpleFontData* SimpleFontData::fontDataForCharacter(UChar32) const
 
 Glyph SimpleFontData::glyphForCharacter(UChar32 character) const
 {
-    GlyphPageTreeNode* node = GlyphPageTreeNode::getRootChild(this, character / GlyphPage::size);
-    return node->page() ? node->page()->glyphAt(character % GlyphPage::size) : 0;
+    // As GlyphPage::size is power of 2 so shifting is valid
+    int val = character >> 8;

[jungshik at Google, 2014/04/07 17:13:58]

Hmm... compiler was not smart enough?  (GlyphPage::size is static const).
Anyway, instead of hardcoding '8', why don't you add a const to GlyphPage for
log2 of |size|)? 

[Stephen Chennney, 2014/04/07 18:02:49]

This hard bakes GlyphPage::size to 256.

At a minimum, you should define GlyphPage::sizeBits immediately after size is
defined for GlyphPage.

[hj, 2014/04/08 02:56:50]

Okey, will make changes. as per the shared links when /,% are together than
compiler is not doing optimization.

On 2014/04/07 17:13:58, Jungshik Shin wrote:

+    GlyphPageTreeNode* node = GlyphPageTreeNode::getRootChild(this, val);
+    return node->page() ? node->page()->glyphAt(character - (val << 8)) : 0;

[Stephen Chennney, 2014/04/07 18:02:49]

character - (val << 8) would be better implemented as character & 0xFF.

[hj, 2014/04/08 02:56:50]

Thank you, will make required changes.

On 2014/04/07 18:02:49, Stephen Chenney wrote:

 }
 
 bool SimpleFontData::isSegmented() const