Re: [boost] sorting floats by casting to integer

Subject: Re: [boost] sorting floats by casting to integer
From: Bo Persson (bop_at_[hidden])
Date: 2009-07-27 06:33:36

Steven Ross wrote:
> On Sun, Jul 26, 2009 at 5:22 PM, Cory Nelson <phrosty_at_[hidden]>
> wrote:
>
>>> Thanks for the suggestion.
>>> I ended up passing those flags you suggested, and obtained this
>>> result: cl : Command line warning D9002 : ignoring unknown option
>>> '-march=nocona' cl : Command line warning D9002 : ignoring
>>> unknown option '-mfpmath=sse'
>>
>> Those are for GCC.  For VC++, you want to use /arch:SSE2.
>>
>
> Thanks Cory.  There was no warning with that option specified, but
> there
> was also no measurable performance change.  I verified that MSVC
> was being called with the option, and that if I misspelled the
> option, a warning was issued.  I think that SSE is deliberately
> disabled in the cheap version of MSVC I bought, based upon the
> Microsoft documentation.

No they are not disabled, not even in the free Express edition.

Disabled optimizations was true for older free versions, producing bad 
benchmarks all over the place. Someone learned from this!  :-)

Bo Persson