[Mesa-dev] [PATCH] i965/fs: Reset the register file to VGRF in lower_integer_multiplication

[Matt Turner]

On Fri, Dec 15, 2017 at 5:12 PM, Jason Ekstrand <jason at jlekstrand.net> wrote:
> 18fde36ced4279f2577097a1a7d31b55f2f5f141 changed the way temporary
> registers were allocated in lower_integer_multiplication so that we
> allocate regs_written(inst) space and keep the stride of the original
> destination register.  This was to ensure that any MUL which originally
> followed the CHV/BXT integer multiply regioning restrictions would
> continue to follow those restrictions even after lowering.  This works
> fine except that I forgot to reset the register file to VGRF so, even
> though they were assigned a number from alloc.allocate(), they had the
> wrong register file.  This caused some GLES 3.0 CTS tests to start
> failing on Sandy Bridge due to attempted reads from the MRF:
>
>     ES3-CTS.functional.shaders.precision.int.highp_mul_fragment.snbm64
>     ES3-CTS.functional.shaders.precision.int.mediump_mul_fragment.snbm64
>     ES3-CTS.functional.shaders.precision.int.lowp_mul_fragment.snbm64
>     ES3-CTS.functional.shaders.precision.uint.highp_mul_fragment.snbm64
>     ES3-CTS.functional.shaders.precision.uint.mediump_mul_fragment.snbm64
>     ES3-CTS.functional.shaders.precision.uint.lowp_mul_fragment.snbm64
>
> This commit remedies this problem by, instead of copying inst->dst and
> overwriting nr, just make a new register and set the region to match
> inst->dst.
>
> Cc: Matt Turner <mattst88 at gmail.com>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103626
> Fixes: 18fde36ced4279f2577097a1a7d31b55f2f5f141
> Cc: "17.3" <mesa-stable at lists.freedesktop.org>

Thanks. Sorry this got lost. Looks like it was sent the day I started vacation.

Reviewed-by: Matt Turner <mattst88 at gmail.com>