i965/fs: Update discard jump to preserve uniform loads via sampler.

Commit 17c7ead7 exposed a bug in how uniform loading happens in the
presence of discard.  It manifested itself in an application as
randomly incorrect pixels on the borders of conditional areas.

This is due to how discards jump to the end of the shader incorrectly
for some channels.  The current implementation checks each 2x2
subspan to preserve derivatives.  When uniform loading via samplers
was turned on, it uses a full execution mask, as stated in
lower_uniform_pull_constant_loads(), and only populates four channels
of the destination (see generate_uniform_pull_constant_load_gen7()).
It happens incorrectly when the first subspan has been jumped over.

The series that implemented this optimization was done before the
changes to use samplers for uniform loads.  Uniform sampler loads
use special execution masks and only populate four channels, so we
can't jump over those or corruption ensues.

This fix only jumps to the end of the shader if all relevant channels
are disabled, i.e. all 8 or 16, depending on dispatch.  This
preserves the original GLbenchmark 2.7 speedup noted in commit
beafced2.

It changes the shader assembly accordingly:

before   : (-f0.1.any4h)  halt(8)  17 2  null { align1 WE_all 1Q };
after(8) : (-f0.1.any8h)  halt(8)  17 2  null { align1 WE_all 1Q };
after(16): (-f0.1.any16h) halt(16) 17 2  null { align1 WE_all 1H };

v2: Cleaned up comments and conditional ordering.
v3: Fix typo.

Signed-off-by: Cody Northrop <cody@lunarg.com>
Reviewed-by: Mike Stroyan <mike@lunarg.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=79948
glsl: Fix aggregates with dynamic initializers.

Vectors are falling in to the ir_dereference_array() path.

Without this change, the following glsl aborts the debug driver,
or gets the wrong answer in release:

mat2x2 a = mat2( vec2( 1.0, vertex.x ), vec2( 0.0, 1.0 ) );

Also submitting piglit tests, will reference in bug.

v2: Rebase on Mesa master.

v3: Remove unneeded check for arrays, which are covered by
    process_array_constructor(), recommended by Timothy Arceri.

Signed-off-by: Cody Northrop <cody@lunarg.com>
Reviewed-by: Courtney Goeltzenleuchter <courtney@lunarg.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=79373
mesa: fix NULL pointer deref bug in _mesa_drawbuffers()

This is a follow-on fix to commit 39b40ad144.  Fixes a crash if the
user calls glDrawBuffers(0, NULL).

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=82814
Cc: "10.2" <mesa-stable@lists.freedesktop.org>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Bug fix: we were looking up non-GPR register numbers in the virtual GRF start/end arrays.
Now, that is protected by (inst->dst.file == GRF).
Move MESA_GLSL flags from gl_pipeline_object to gl_context for thread safety
MESA: Add tar files and glassy build script