[Mesa-dev] [PATCH] i965/fs: Fix regs_written for SIMD-lowered instructions some more.

[Francisco Jerez]

Iago Toral <itoral at igalia.com> writes:

> On Fri, 2016-06-10 at 22:39 -0700, Francisco Jerez wrote:
>> ISTR having suggested this during review of the recent FP64 changes to
>> the SIMD lowering pass, but it doesn't look like it was taken into
>> account in the end.  Using the fs_reg::component_size helper instead
>> of this open-coded variant makes sure that the stride is taken into
>> account correctly.  Fixes at least the following piglit tests with
>> spilling forced on (since otherwise regs_written would be calculated
>> incorrectly and the spilling code would be rather confused about how
>> much data needs to be spilled):
>
> Yes, you had suggested it but we forgot about it until a few days ago
> when I was tracking down a similar bug and came up with this same patch.
> I was about to send it for review together with other fixes for BSW this
> week, sorry if that caused you trouble...
>
No worries, it was no trouble at all.

> Iago
>
>>  spec.arb_gpu_shader_fp64.shader_storage.layout-std140-fp64-shader
>>  spec.arb_gpu_shader_fp64.shader_storage.layout-std140-fp64-mixed-shader
>> 
>> Cc: <mesa-stable at lists.freedesktop.org>
>> ---
>>  src/mesa/drivers/dri/i965/brw_fs.cpp | 6 +++---
>>  1 file changed, 3 insertions(+), 3 deletions(-)
>> 
>> diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
>> index 104c20b..0347b0a 100644
>> --- a/src/mesa/drivers/dri/i965/brw_fs.cpp
>> +++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
>> @@ -5261,9 +5261,9 @@ fs_visitor::lower_simd_width()
>>                 split_inst.src[j] = emit_unzip(lbld, block, inst, j);
>>  
>>              split_inst.dst = emit_zip(lbld, block, inst);
>> -            split_inst.regs_written =
>> -               DIV_ROUND_UP(type_sz(inst->dst.type) * dst_size * lower_width,
>> -                            REG_SIZE);
>> +            split_inst.regs_written = DIV_ROUND_UP(
>> +               split_inst.dst.component_size(lower_width) * dst_size,
>> +               REG_SIZE);
>>  
>>              lbld.emit(split_inst);
>>           }
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