[LLVMdev] Using MSVC _ftol2 runtime function for fptoui on Win32

[Badouh, Asaf]

Hi Joe & Michael,

In rev. 151382 you have changed the fptoui implementation of the x86 codegen for win32.

Before the change fptoui was lowered to

flds   16(%esp)

       fisttpll      8(%esp)

movl   8(%esp), %eax

After the change fptoui is lowered to

flds   40(%esp)
calll  _ftol2

Please note that the assumption that _ftol2 doesn't modify ECX isn't true on sandybridge platform.
Could you share with me the reasons behind this change? Did you get better performance after this change?

Thanks,
Asaf
---------------------------------------------------------------------
Intel Israel (74) Limited

This e-mail and any attachments may contain confidential material for
the sole use of the intended recipient(s). Any review or distribution
by others is strictly prohibited. If you are not the intended
recipient, please contact the sender and delete all copies.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20130213/b3346fa5/attachment.html>