[Mesa-dev] [PATCH 03/23] i965/fs: Fix copy propagation of load payload for double operands

[Samuel Iglesias Gonsálvez]

On 04/05/16 00:51, Jordan Justen wrote:
> On 2016-05-03 05:21:52, Samuel Iglesias Gonsálvez wrote:
>> From: Iago Toral Quiroga <itoral at igalia.com>
>>
>> Specifically, consider the size of the data type of the operand to compute
>> the number of registers written.
>> ---
>>  src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp b/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
>> index 9147e60..abc68c8 100644
>> --- a/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
>> +++ b/src/mesa/drivers/dri/i965/brw_fs_copy_propagation.cpp
>> @@ -775,7 +775,7 @@ fs_visitor::opt_copy_propagate_local(void *copy_prop_ctx, bblock_t *block,
>>           int offset = 0;
>>           for (int i = 0; i < inst->sources; i++) {
>>              int effective_width = i < inst->header_size ? 8 : inst->exec_size;
>> -            int regs_written = effective_width / 8;
>> +            int regs_written = effective_width / 8 * type_sz(inst->src[i].type) / 4;
> 
> Line length.
> 

OK

> Should this be based on inst->dst?
> 

No, it shouldn't. When SHADER_OPCODE_LOAD_PAYLOAD is lowered, the
destination is retyped to source's type. Furthermore inside
LOAD_PAYLOAD(), regs_written is calculated with the type size of the
sources.

> type_sz(foo.type) will only ever be 4 or 8?
> 

I have not found any usage with a type suze less than 4. I added an
assert just in case this is changed in the future. No piglit regressions
with that assert in place.

Sam

> -Jordan
> 
>>              if (inst->src[i].file == VGRF) {
>>                 acp_entry *entry = ralloc(copy_prop_ctx, acp_entry);
>>                 entry->dst = inst->dst;
>> -- 
>> 2.5.0
>>
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>