[Mesa-dev] [PATCH 4/5] i965/vec4_nir: Do boolean source modifier resolves on BDW+

[Matt Turner]

On Mon, Aug 10, 2015 at 11:19 AM, Jason Ekstrand <jason at jlekstrand.net> wrote:
> On Mon, Aug 10, 2015 at 11:16 AM, Matt Turner <mattst88 at gmail.com> wrote:
>> On Mon, Aug 3, 2015 at 5:22 PM, Jason Ekstrand <jason at jlekstrand.net> wrote:
>>> On BDW+, the negation source modifier on NOT, AND, OR, and XOR, is actually
>>> a boolean negate and not an integer negate.  However, NIR's soruce
>>> modifiers are the integer version.  We have to resolve it with a MOV prior
>>> to emitting the actual instruction.  This is basically the same thing we do
>>> in the FS backend.
>>> ---
>>>  src/mesa/drivers/dri/i965/brw_vec4.h           |  1 +
>>>  src/mesa/drivers/dri/i965/brw_vec4_nir.cpp     | 15 +++++++++++++++
>>>  src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp | 13 +++++++++++++
>>>  3 files changed, 29 insertions(+)
>>>
>>> diff --git a/src/mesa/drivers/dri/i965/brw_vec4.h b/src/mesa/drivers/dri/i965/brw_vec4.h
>>> index 985886d..ff143be 100644
>>> --- a/src/mesa/drivers/dri/i965/brw_vec4.h
>>> +++ b/src/mesa/drivers/dri/i965/brw_vec4.h
>>> @@ -320,6 +320,7 @@ public:
>>>                     dst_reg dst, src_reg src0, src_reg src1);
>>>
>>>     src_reg fix_3src_operand(src_reg src);
>>> +   src_reg resolve_source_modifiers(src_reg src);
>>>
>>>     vec4_instruction *emit_math(enum opcode opcode, const dst_reg &dst, const src_reg &src0,
>>>                                 const src_reg &src1 = src_reg());
>>> diff --git a/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp b/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp
>>> index 27f23d0..1b7fb5e 100644
>>> --- a/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp
>>> +++ b/src/mesa/drivers/dri/i965/brw_vec4_nir.cpp
>>> @@ -1020,18 +1020,33 @@ vec4_visitor::nir_emit_alu(nir_alu_instr *instr)
>>>     }
>>>
>>>     case nir_op_inot:
>>> +      if (devinfo->gen >= 8) {
>>> +         op[0] = resolve_source_modifiers(op[0]);
>>> +      }
>>>        emit(NOT(dst, op[0]));
>>>        break;
>>>
>>>     case nir_op_ixor:
>>> +      if (devinfo->gen >= 8) {
>>> +         op[0] = resolve_source_modifiers(op[0]);
>>> +         op[1] = resolve_source_modifiers(op[1]);
>>> +      }
>>>        emit(XOR(dst, op[0], op[1]));
>>>        break;
>>>
>>>     case nir_op_ior:
>>> +      if (devinfo->gen >= 8) {
>>> +         op[0] = resolve_source_modifiers(op[0]);
>>> +         op[1] = resolve_source_modifiers(op[1]);
>>> +      }
>>>        emit(OR(dst, op[0], op[1]));
>>>        break;
>>>
>>>     case nir_op_iand:
>>> +      if (devinfo->gen >= 8) {
>>> +         op[0] = resolve_source_modifiers(op[0]);
>>> +         op[1] = resolve_source_modifiers(op[1]);
>>> +      }
>>>        emit(AND(dst, op[0], op[1]));
>>>        break;
>>>
>>> diff --git a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
>>> index c5c0d2c..639f829 100644
>>> --- a/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
>>> +++ b/src/mesa/drivers/dri/i965/brw_vec4_visitor.cpp
>>> @@ -313,6 +313,19 @@ vec4_visitor::fix_3src_operand(src_reg src)
>>>  }
>>>
>>>  src_reg
>>> +vec4_visitor::resolve_source_modifiers(src_reg src)
>>> +{
>>> +   if (!src.abs && !src.negate)
>>> +      return src;
>>> +
>>> +   dst_reg resolved = dst_reg(this, glsl_type::ivec4_type);
>>> +   resolved.type = src.type;
>>> +   emit(MOV(resolved, src));
>>> +
>>> +   return src_reg(resolved);
>>> +}
>>
>> The FS passes a pointer to an fs_reg and then updates that. Let's do
>> that here to be consistent.
>
> Oh... I was just trying to be consistent with other functions in
> vec4_visitor such as fix_3src_operand() above.

Heh, consistency is inconsistent!

If changing the FS to be consistent with this seems better, that works for me.

In that case, make the argument 'const src_reg &src' to avoid the copy.