Bug 110825

Created attachment 144425 [details]
valgrind output

Assigning to Jason as it is his commit.

https://gitlab.freedesktop.org/mesa/mesa/merge_requests/993

commit a84de3fb7c1198f7cbd3b20a4231c14a7010f97f
Author: Jason Ekstrand <jason@jlekstrand.net>
Date:   Mon Jun 3 17:09:12 2019 -0500

    intel/fs: Skip registers faster when setting spill costs
    
    This might be slightly faster since we're doing one read rather than
    two before we decide to skip.  The more important reason, however, is
    because no_spill prevents us from re-spilling spill registers.  In the
    new world in which we don't re-calculate liveness every spill, we may
    not have valid liveness for spill registers so we shouldn't even look
    their live ranges up.
    
    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=110825
    Fixes: e99081e76d4 "intel/fs/ra: Spill without destroying the..."
    Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
    Tested-by: Tapani Pälli <tapani.palli@intel.com>

FYI now that I tested with KBL, I see following error/warning. I do see it before the offending commit though so this is something that has existed before. For some reason I did not spot these in HSW. That test eventually crashes on HSW but passes on KBL with this single warning.

--- 8< ---
==12320== Memcheck, a memory error detector
==12320== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==12320== Using Valgrind-3.14.0 and LibVEX; rerun with -h for copyright info
==12320== Command: bin/shader_runner /home/tpalli/slow.shader_test -auto
==12320== 
==12320== Conditional jump or move depends on uninitialised value(s)
==12320==    at 0xC2A36FC: ra_get_best_spill_node (register_allocate.c:960)
==12320==    by 0xBF99499: fs_reg_alloc::choose_spill_reg() (brw_fs_reg_allocate.cpp:937)
==12320==    by 0xBF9A0A8: fs_reg_alloc::assign_regs(bool, bool) (brw_fs_reg_allocate.cpp:1161)
==12320==    by 0xBF9A3AA: fs_visitor::assign_regs(bool, bool) (brw_fs_reg_allocate.cpp:1201)
==12320==    by 0xBF619A7: fs_visitor::allocate_registers(unsigned int, bool) (brw_fs.cpp:7282)
==12320==    by 0xBF62D20: fs_visitor::run_fs(bool, bool) (brw_fs.cpp:7694)
==12320==    by 0xBF63CC8: brw_compile_fs (brw_fs.cpp:8028)
==12320==    by 0xB7BCE62: brw_codegen_wm_prog (brw_wm.c:123)
==12320==    by 0xB7BE25D: brw_fs_precompile (brw_wm.c:592)
==12320==    by 0xB7A423C: brw_shader_precompile(gl_context*, gl_shader_program*) (brw_link.cpp:56)
==12320==    by 0xB7A541F: brw_link_shader (brw_link.cpp:374)
==12320==    by 0xBAC983D: _mesa_glsl_link_shader (ir_to_mesa.cpp:3170)
==12320==