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- To: eigen <eigen@xxxxxxxxxxxxxxxxxxx>
- Subject: [eigen] Re: 4x4 matrix inverse
- From: Benoit Jacob <jacob.benoit.1@xxxxxxxxx>
- Date: Mon, 14 Dec 2009 23:37:23 -0500
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2009/12/14 Benoit Jacob <jacob.benoit.1@xxxxxxxxx>:
> I have a question. I currently get warnings in this code (taken
> straight from Intel):
>
> __m128 tmp1;
> tmp1 = _mm_loadh_pi(_mm_loadl_pi(tmp1, (__m64*)(src)), (__m64*)(src+ 4));
>
> The warning claims that tmp1 is used uninitalized here. GCC doesn't
> understand that it only is passed to _mm_loadl_pi that writes into it,
> does not read from it. How to fix that warning? I tested initializing
> tmp1, this had a not-totally-negligible impact on performance (because
> there are 2 more variables that need this). There does not seem to be
> an __attribute__ for this.
Actually, I just rebuilt the unit tests, and I get a ton of mutually
unrelated "uninitialized variable" warnings, with GCC 4.4.2 ! Does
anyone know what's happening?
Benoit