Running glsl-fs-uniform-array-loop-unroll.shader_test on either Haswell or Crestline, I see a random offset used for the pull constant buffer. valgrind reports that it's reading out of bounds.
I haven't bisected to see if this was introduced recently.
I am looking into this
We are not checking out-of-bounds accesses into the pull_constant_loc array.
I sent a patch for review that fixes this:
BTW, this is the error that gets fixed, as reported by Valgrind:
==18969== Invalid read of size 4
==18969== at 0xA8FA80D: fs_visitor::demote_pull_constants() (brw_fs.cpp:1966)
==18969== by 0xA8FDEAB: fs_visitor::run() (brw_fs.cpp:3044)
==18969== by 0xA8FE3BB: brw_wm_fs_emit (brw_fs.cpp:3169)
==18969== by 0xA97E219: do_wm_prog (brw_wm.c:183)
==18969== by 0xA8FEC88: brw_fs_precompile(gl_context*, gl_shader_program*) (brw_fs.cpp:3294)
==18969== by 0xA93F2BA: brw_shader_precompile(gl_context*, gl_shader_program*) (brw_shader.cpp:72)
==18969== by 0xA93FB51: brw_link_shader (brw_shader.cpp:274)
==18969== by 0xA7B03C7: _mesa_glsl_link_shader (ir_to_mesa.cpp:3092)
==18969== by 0xA64AC43: link_program (shaderapi.c:915)
==18969== by 0xA64BDC4: _mesa_LinkProgram (shaderapi.c:1383)
==18969== by 0x81DA11E: shared_dispatch_stub_509 (glapi_mapi_tmp.h:17831)
==18969== by 0x4EDE27D: stub_glLinkProgram (piglit-dispatch-gen.c:31514)
Author: Iago Toral Quiroga <firstname.lastname@example.org>
Date: Tue Mar 10 11:36:43 2015 +0100
i965: Fix out-of-bounds accesses into pull_constant_loc array
The piglit test glsl-fs-uniform-array-loop-unroll.shader_test was designed
to do an out of bounds access into an uniform array to make sure that we
handle that situation gracefully inside the driver, however, as Ken describes
in bug 79202, Valgrind reports that this is leading to an out-of-bounds access
Before accessing the pull_constant_loc array we should make sure that
the uniform we are trying to access is valid.
Reviewed-by: Matt Turner <email@example.com>