RESOLVED WONTFIX 14602
JSC/WTF: fastMalloc doesn't use bsr under VC 
https://bugs.webkit.org/show_bug.cgi?id=14602
Summary JSC/WTF: fastMalloc doesn't use bsr under VC
808caaa4.8ce9.9cd6c799e9f6
Reported 2007-07-13 04:08:35 PDT
With VC, fastMalloc.cpp doesn't use inline assembly for LgFloor(). #if defined(_MSC_VER) && !defined(_68K_) && !defined(_MPPC_) && !defined(_X86_) && !defined(_IA64_) && !defined(_AMD64_) && defined(_M_IX86) static inline int LgFloor(size_t n) { __asm xor eax,eax __asm not eax __asm bsr eax,n } #endif p.s. In WebKit.dll, do_malloc() and do_free() expands as ALWAYS_INLINE everywhere and costs binary sizes. Is this intended?
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Add attachment proposed patch, testcase, etc.
David Kilzer (:ddkilzer)
Comment 1 2007-07-14 15:22:52 PDT
<rdar://problem/5335830>
Maciej Stachowiak
Comment 2 2007-07-16 19:40:41 PDT
Yes, we don't have all the inline assembly implemented for Windows yet. It could be a small performance boost once done.
Maciej Stachowiak
Comment 3 2007-08-30 02:52:35 PDT
Why are the xor and the not needed in the inline assembly here? They don't seem to be needed in the gcc version.
Robert Blaut
Comment 4 2008-02-20 03:32:19 PST
P5 is not used for WebKit bugs. [http://webkit.org/quality/bugpriorities.html]
Gavin Barraclough
Comment 5 2012-09-06 12:50:49 PDT
I don't think this method has shown up under recent profiling, and this bug has sat idle for 5 years. I don't think this is a change we intend to make. Please reopen if you intend to work on this bug.
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