diff options
| author | Kenneth Graunke <[email protected]> | 2014-06-14 03:53:07 -0700 |
|---|---|---|
| committer | Kenneth Graunke <[email protected]> | 2014-06-15 16:51:05 -0700 |
| commit | d0575d98fc595dcc17706dc73d1eb461027ca17a (patch) | |
| tree | 5c5f147de9d522587022be50ac0af30f77a407aa /src/mesa/drivers/dri/i965/brw_vec4.cpp | |
| parent | d6a7a2606e8007243120ee5032c811fe5655854d (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 <[email protected]>
Reviewed-by: Matt Turner <[email protected]>
Cc: [email protected]
Diffstat (limited to 'src/mesa/drivers/dri/i965/brw_vec4.cpp')
| -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 e816b94e608..ee5be56b713 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) || |