Qt 4.7 don't use SSE2 to speed up blending in x86-64

I built Qt 4.7 in windows 7 x64 with visual studio 2008. I found that with this version Qt will not use the SSE2 version of blending function to do bleding work even I have specified -SSE and -SSE2 option when configuring the bulid process.
The problem is in qglobal.h Qt think if I build it from visual studio and in a x86-64 machine the QT_HAVE_SSE must be undefined ( this is very strange, visual studio do support SSE in x86-64). What is worse is that the qInitDrawhelperAsm() function in qdrawhelper.cpp file there is a #ifdef QT_HAVE_SSE ... #endif pair, in that pair Qt will check if this machine support SSE2 and set the function pointer to the SSE2 version, but in x86-64 QT_HAVE_SSE is not defined so the function pointer will not be set to SSE2 version. Thus there will be no SSE2 or SSSE3 speed up in windows x64 which is definitely not good.