[Mesa-dev] [PATCH 4/5] i965/fs: Use correct spill offsets

[Matt Turner]

On Fri, Oct 24, 2014 at 1:11 PM, Jason Ekstrand <jason at jlekstrand.net> wrote:
>
>
> On Fri, Oct 24, 2014 at 12:25 PM, Jason Ekstrand <jason at jlekstrand.net>
> wrote:
>>
>> ---
>>  src/mesa/drivers/dri/i965/brw_fs_reg_allocate.cpp | 11 +++++------
>>  1 file changed, 5 insertions(+), 6 deletions(-)
>>
>> diff --git a/src/mesa/drivers/dri/i965/brw_fs_reg_allocate.cpp
>> b/src/mesa/drivers/dri/i965/brw_fs_reg_allocate.cpp
>> index d4b72d8..49b50ee 100644
>> --- a/src/mesa/drivers/dri/i965/brw_fs_reg_allocate.cpp
>> +++ b/src/mesa/drivers/dri/i965/brw_fs_reg_allocate.cpp
>> @@ -651,7 +651,7 @@ fs_visitor::emit_unspill(bblock_t *block, fs_inst
>> *inst, fs_reg dst,
>>        inst->insert_before(block, unspill_inst);
>>
>>        dst.reg_offset += reg_size;
>> -      spill_offset += reg_size * 8 * sizeof(float);
>> +      spill_offset += reg_size * REG_SIZE;
>
>
> This change is purely cosmetic
>
>>
>>     }
>>  }
>>
>> @@ -671,7 +671,7 @@ fs_visitor::emit_spill(bblock_t *block, fs_inst *inst,
>> fs_reg src,
>>           new(mem_ctx) fs_inst(SHADER_OPCODE_GEN4_SCRATCH_WRITE,
>>                                reg_null_f, src);
>>        src.reg_offset += reg_size;
>> -      spill_inst->offset = spill_offset + i * reg_size;
>> +      spill_inst->offset = spill_offset + i * reg_size * REG_SIZE;
>
>
> The offset is supposed to be in bytes, but we were giving it an offset in
> registers.  This fixes that.
>
>>
>>        spill_inst->ir = inst->ir;
>>        spill_inst->annotation = inst->annotation;
>>        spill_inst->mlen = 1 + reg_size; /* header, value */
>> @@ -759,7 +759,6 @@ fs_visitor::choose_spill_reg(struct ra_graph *g)
>>  void
>>  fs_visitor::spill_reg(int spill_reg)
>>  {
>> -   int reg_size = dispatch_width * sizeof(float);
>>     int size = virtual_grf_sizes[spill_reg];
>>     unsigned int spill_offset = last_scratch;
>>     assert(ALIGN(spill_offset, 16) == spill_offset); /* oword read/write
>> req. */
>> @@ -786,7 +785,7 @@ fs_visitor::spill_reg(int spill_reg)
>>        spilled_any_registers = true;
>>     }
>>
>> -   last_scratch += size * reg_size;
>> +   last_scratch += size * REG_SIZE;
>
>
> The offset is supposed to be in bytes but virtual_grf_size is in actual
> hardware registers.  Therefore, the offset is virtual_grf_size * REG_SIZE.
> Before, we had an extra factor of 2 in SIMD16 mode
>
>>
>>
>>     /* Generate spill/unspill instructions for the objects being
>>      * spilled.  Right now, we spill or unspill the whole thing to a
>> @@ -799,7 +798,7 @@ fs_visitor::spill_reg(int spill_reg)
>>              inst->src[i].reg == spill_reg) {
>>              int regs_read = inst->regs_read(this, i);
>>              int subset_spill_offset = (spill_offset +
>> -                                       reg_size *
>> inst->src[i].reg_offset);
>> +                                       REG_SIZE *
>> inst->src[i].reg_offset);
>
>
> same as above
>
>>
>>              fs_reg unspill_dst(GRF, virtual_grf_alloc(regs_read));
>>
>>              inst->src[i].reg = unspill_dst.reg;
>> @@ -813,7 +812,7 @@ fs_visitor::spill_reg(int spill_reg)
>>        if (inst->dst.file == GRF &&
>>           inst->dst.reg == spill_reg) {
>>           int subset_spill_offset = (spill_offset +
>> -                                    reg_size * inst->dst.reg_offset);
>> +                                    REG_SIZE * inst->dst.reg_offset);
>
>
> same as above

Thanks. Put some explanation in the commit summary and the series is

Reviewed-by: Matt Turner <mattst88 at gmail.com>