[Mesa-dev] X test suite regression due to gallivm change

[Adam Jackson]

Starting from:

> commit 320d1191c61a0a82444605c12e5c4b2ee0b241eb
> Author: Jose Fonseca <jfonseca at vmware.com>
> Date:   Mon Apr 4 00:05:33 2016 +0100
> 
>     gallivm: Use llvm.fmuladd.*.
>     
>     Reviewed-by: Roland Scheidegger <sroland at vmware.com>

'make check' in xserver no longer passes on Xephyr+glamor+llvmpipe. At
least, not on my Skylake. Setting LP_NATIVE_VECTOR_WIDTH=128 fixes it,
so I assume this is a difference in generated code between AVX2 and
non-AVX. I haven't dug much further into it yet, just wondering if
there's any obvious reason AVX would generate noticably different
rendering after this change, or if this change had been seen to cause
trouble on other AVX machines.

- ajax