diff options
| author | Kenneth Graunke <kenneth@whitecape.org> | 2014-06-14 03:53:07 -0700 |
|---|---|---|
| committer | Carl Worth <cworth@cworth.org> | 2014-06-23 14:56:11 -0700 |
| commit | 01a79ac679916b08cc0bb194c317aee13a5c2704 (patch) | |
| tree | 450bd5716557b929a38c8edfe14801a1dc9eb1a8 | |
| parent | 83be6a5517ae8908bfbdbb57f5fcef1539e4c044 (diff) | |
i965/vec4: Fix dead code elimination for VGRFs of size > 1.
When faced with code such as:
mov vgrf31.0:UD, 960D
mov vgrf31.1:UD, vgrf30.xxxx:UD
The dead code eliminator didn't consider reg_offsets, so it decided that
the second instruction was writing was writing to the same register as
the first one, and eliminated the first one. But they're actually
different registers.
This fixes INTEL_DEBUG=shader_time for vertex shaders. In the above
code, vgrf31.0 represents the offset into the shader_time buffer where
the data should be written, and vgrf31.1 represents the actual time
data. With a completely undefined offset, results were...unexpected.
I think this is probably one of the few cases (maybe only case) where we
generate multiple MOVs to a large VGRF. Normally, we just use them as
texturing results; the other SEND-from-GRF uses a size 1 VGRF.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=79029
Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Matt Turner <mattst88@gmail.com>
Cc: mesa-stable@lists.freedesktop.org
(cherry picked from commit d0575d98fc595dcc17706dc73d1eb461027ca17a)
| -rw-r--r-- | src/mesa/drivers/dri/i965/brw_vec4.cpp | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/src/mesa/drivers/dri/i965/brw_vec4.cpp b/src/mesa/drivers/dri/i965/brw_vec4.cpp index daff3641119..324e3a51c91 100644 --- a/src/mesa/drivers/dri/i965/brw_vec4.cpp +++ b/src/mesa/drivers/dri/i965/brw_vec4.cpp @@ -464,7 +464,8 @@ vec4_visitor::dead_code_eliminate() } if (inst->dst.file == scan_inst->dst.file && - inst->dst.reg == scan_inst->dst.reg) { + inst->dst.reg == scan_inst->dst.reg && + inst->dst.reg_offset == scan_inst->dst.reg_offset) { int new_writemask = scan_inst->dst.writemask & ~dead_channels; progress = try_eliminate_instruction(scan_inst, new_writemask, brw) || |