GitLab

Submitted by Vinson Lee

Assigned to mes..@..op.org

Link to original bug (#96684)

Description

mesa: 367cf3a2 (12.1.0-devel)

$ ./bin/shader_runner tests/shaders/glsl-array-bounds-01.shader_test -auto Probe color at (15,15) Expected: 0.000000 1.000000 0.000000 Observed: 1.000000 0.000000 0.000000 PIGLIT: {"result": "fail" }

c264fdbc is the first bad commit commit c264fdbc Author: Kenneth Graunke kenneth@whitecape.org Date: Mon Jun 20 11:20:51 2016 -0700

glsl: Split arrays even in the presence of whole-array copies.

Previously, we failed to split constant arrays.  Code such as

   int[2] numbers = int[](1, 2);

would generates a whole-array assignment:

  (assign () (var_ref numbers)
             (constant (array int 4) (constant int 1) (constant int 2)))

opt_array_splitting generally tried to visit ir_dereference_array nodes,
and avoid recursing into the inner ir_dereference_variable.  So if it
ever saw a ir_dereference_variable, it assumed this was a whole-array
read and bailed.  However, in the above case, there's no array deref,
and we can totally handle it - we just have to "unroll" the assignment,
creating assignments for each element.

This was mitigated by the fact that we constant propagate whole arrays,
so a dereference of a single component would usually get the desired
single value anyway.  However, I plan to stop doing that shortly;
early experiments with disabling constant propagation of arrays
revealed this shortcoming.

This patch causes some arrays in Gl32GSCloth's geometry shaders to be
split, which allows other optimizations to eliminate unused GS inputs.
The VS then doesn't have to write them, which eliminates the entire VS
(5 -> 2 instructions).  It still renders correctly.

No other change in shader-db.

v2: Drop !AOA check and improve a comment (feedback from Tim Arceri).

Cc: mesa-stable@lists.freedesktop.org
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Timothy Arceri <timothy.arceri@collabora.com>

:040000 040000 5d96cd8ba322e2ac1857baf9e401b5d494a85ab2 2b920fe841296c89251cca630f51060de413cbb3 M src bisect run success

Version: 12.0

Blocking

• Bug 98471