Title: [152529] trunk/Source/WTF
- Revision
- 152529
- Author
- [email protected]
- Date
- 2013-07-10 01:36:13 -0700 (Wed, 10 Jul 2013)
Log Message
Workaround for x86 optimizer bug in MSVC 2012.
https://bugs.webkit.org/show_bug.cgi?id=118478
Reviewed by Benjamin Poulain.
This is a workaround for a bug in the x86 MSVC 2012 optimizer.
The problem is that the range comparison gets optimized out when
the templated inline function toASCIIUpper. Copying the methods
content fixes the problem.
This is unfortunately not the nicest fix, but the alternative would
be to turn off optimization for StringImpl::upper on the x86 MSVC 2012
build, which might impact overall performance negatively.
* wtf/text/StringImpl.cpp:
(WTF::StringImpl::upper):
Modified Paths
Diff
Modified: trunk/Source/WTF/ChangeLog (152528 => 152529)
--- trunk/Source/WTF/ChangeLog 2013-07-10 08:13:15 UTC (rev 152528)
+++ trunk/Source/WTF/ChangeLog 2013-07-10 08:36:13 UTC (rev 152529)
@@ -1,3 +1,23 @@
+2013-07-10 Michael Brüning <[email protected]>
+
+ Workaround for x86 optimizer bug in MSVC 2012.
+ https://bugs.webkit.org/show_bug.cgi?id=118478
+
+ Reviewed by Benjamin Poulain.
+
+ This is a workaround for a bug in the x86 MSVC 2012 optimizer.
+
+ The problem is that the range comparison gets optimized out when
+ the templated inline function toASCIIUpper. Copying the methods
+ content fixes the problem.
+
+ This is unfortunately not the nicest fix, but the alternative would
+ be to turn off optimization for StringImpl::upper on the x86 MSVC 2012
+ build, which might impact overall performance negatively.
+
+ * wtf/text/StringImpl.cpp:
+ (WTF::StringImpl::upper):
+
2013-07-08 Carlos Garcia Campos <[email protected]>
Unreviewed. Fix make distcheck.
Modified: trunk/Source/WTF/wtf/text/StringImpl.cpp (152528 => 152529)
--- trunk/Source/WTF/wtf/text/StringImpl.cpp 2013-07-10 08:13:15 UTC (rev 152528)
+++ trunk/Source/WTF/wtf/text/StringImpl.cpp 2013-07-10 08:36:13 UTC (rev 152529)
@@ -485,7 +485,14 @@
for (int i = 0; i < length; ++i) {
LChar c = m_data8[i];
ored |= c;
+#if CPU(X86) && defined(_MSC_VER) && _MSC_VER >=1700
+ // Workaround for an MSVC 2012 x86 optimizer bug. Remove once the bug is fixed.
+ // See https://connect.microsoft.com/VisualStudio/feedback/details/780362/optimization-bug-of-range-comparison
+ // for more details.
+ data8[i] = c >= 'a' && c <= 'z' ? c & ~0x20 : c;
+#else
data8[i] = toASCIIUpper(c);
+#endif
}
if (!(ored & ~0x7F))
return newImpl.release();
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