On Wed, May 21, 2014 at 4:08 PM, Eric Anholt <e...@anholt.net> wrote:
> Matt Turner <matts...@gmail.com> writes:
>
>> Number of compacted instructions: 827404 -> 833045 (0.68%)
>> ---
>> src/mesa/drivers/dri/i965/brw_eu_emit.c | 20 ++++++++++++++++++++
>> 1 file changed, 20 insertions(+)
>>
>> diff --git a/src/mesa/drivers/dri/i965/brw_eu_emit.c
>> b/src/mesa/drivers/dri/i965/brw_eu_emit.c
>> index 1810233..ab00d7c 100644
>> --- a/src/mesa/drivers/dri/i965/brw_eu_emit.c
>> +++ b/src/mesa/drivers/dri/i965/brw_eu_emit.c
>> @@ -295,6 +295,16 @@ validate_reg(struct brw_instruction *insn, struct
>> brw_reg reg)
>> /* 10. Check destination issues. */
>> }
>>
>> +static bool
>> +is_compactable_immediate(unsigned imm)
>> +{
>> + /* We get the low 12 bits as-is. */
>> + imm &= ~0xfff;
>> +
>> + /* We get one bit replicated through the top 20 bits. */
>> + return imm == 0 || imm == 0xfffff000;
>> +}
>> +
>> void
>> brw_set_src0(struct brw_compile *p, struct brw_instruction *insn,
>> struct brw_reg reg)
>> @@ -373,6 +383,16 @@ brw_set_src0(struct brw_compile *p, struct
>> brw_instruction *insn,
>> insn->bits1.da1.src0_reg_type == BRW_HW_REG_TYPE_F) {
>> insn->bits1.da1.src0_reg_type = BRW_HW_REG_IMM_TYPE_VF;
>> }
>> +
>> + /* There are no mappings for dst:d | i:d, so if the immediate is
>> suitable
>> + * set the types to :UD so the instruction can be compacted.
>> + */
>> + if (is_compactable_immediate(insn->bits3.ud) &&
>> + insn->bits1.da1.src0_reg_type == BRW_HW_REG_TYPE_D &&
>> + insn->bits1.da1.dest_reg_type == BRW_HW_REG_TYPE_D) {
>> + insn->bits1.da1.src0_reg_type = BRW_HW_REG_TYPE_UD;
>> + insn->bits1.da1.dest_reg_type = BRW_HW_REG_TYPE_UD;
>> + }
>
> Do conditional modifier flags work the same for the same data with D
> versus UD destinations? Just trying to come up with cases where
> changing the type would matter.
I think it'd be different if we did something like
mov.le.f0 dst:D, -1D
and converted it to
mov.le.f0 dst:UD, 0xffffffffUD
you'd get the same bits in dst, but a different value in f0.
I can't imagine we'll ever emit a mov/cmod/immediate-source, but that
also means we'd never lose anything by disabling it this if there's
cmod.
I'll change the conditional to include &&
insn->header.destreg__conditionalmod == 0.
With that fixed, it gets your R-b?
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