[Mesa-dev] [RFC 2/5] nir: Add unordered comparisons and ordered fne

[Jason Ekstrand]

On November 22, 2018 13:48:48 Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl> 
wrote:

> On Thu, Nov 22, 2018 at 7:47 PM Jason Ekstrand <jason at jlekstrand.net> wrote:
>>
>>
>> ---
>> src/compiler/nir/nir.h                |  8 ++++++++
>> src/compiler/nir/nir_loop_analyze.c   | 12 ++++++++----
>> src/compiler/nir/nir_opcodes.py       |  4 ++++
>> src/compiler/nir/nir_opt_algebraic.py |  5 +++++
>> 4 files changed, 25 insertions(+), 4 deletions(-)
>>
>>
>> diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
>> index 4271f237235..20ff9a87297 100644
>> --- a/src/compiler/nir/nir.h
>> +++ b/src/compiler/nir/nir.h
>> @@ -1561,6 +1561,10 @@ nir_alu_instr_is_comparison(const nir_alu_instr *instr)
>> case nir_op_flt:
>> case nir_op_fge:
>> case nir_op_feq:
>> +   case nir_op_fne:
>> +   case nir_op_fltu:
>> +   case nir_op_fgeu:
>> +   case nir_op_fequ:
>> case nir_op_fneu:
>> case nir_op_ilt:
>> case nir_op_ult:
>> @@ -2132,6 +2136,10 @@ typedef struct nir_shader_compiler_options {
>>
>>
>> bool lower_ldexp;
>>
>>
>> +   bool lower_fltu;
>> +   bool lower_fgeu;
>> +   bool lower_fne_to_fequ;
>> +
>> bool lower_pack_half_2x16;
>> bool lower_pack_unorm_2x16;
>> bool lower_pack_snorm_2x16;
>> diff --git a/src/compiler/nir/nir_loop_analyze.c 
>> b/src/compiler/nir/nir_loop_analyze.c
>> index d73314a8a44..d6cba541a10 100644
>> --- a/src/compiler/nir/nir_loop_analyze.c
>> +++ b/src/compiler/nir/nir_loop_analyze.c
>> @@ -376,6 +376,10 @@ get_iteration(nir_op cond_op, nir_const_value 
>> *initial, nir_const_value *step,
>> case nir_op_fge:
>> case nir_op_flt:
>> case nir_op_feq:
>> +   case nir_op_fne:
>> +   case nir_op_fgeu:
>> +   case nir_op_fltu:
>> +   case nir_op_fequ:
>> case nir_op_fneu: {
>> float initial_val = initial->f32[0];
>> float span = limit->f32[0] - initial_val;
>> @@ -547,10 +551,10 @@ find_trip_count(loop_info_state *state)
>> bool limit_rhs = true;
>>
>>
>> switch (alu->op) {
>> -      case nir_op_fge:      case nir_op_ige:      case nir_op_uge:
>> -      case nir_op_flt:      case nir_op_ilt:      case nir_op_ult:
>> -      case nir_op_feq:      case nir_op_ieq:
>> -      case nir_op_fneu:     case nir_op_ine:
>> +      case nir_op_fgeu: case nir_op_fge:  case nir_op_ige:  case nir_op_uge:
>> +      case nir_op_fltu: case nir_op_flt:  case nir_op_ilt:  case nir_op_ult:
>> +      case nir_op_fequ: case nir_op_feq:  case nir_op_ieq:
>> +      case nir_op_fneu: case nir_op_fne:  case nir_op_ine:
>>
>>
>>  /* We assume that the limit is the "right" operand */
>>  basic_ind = get_loop_var(alu->src[0].src.ssa, state);
>> diff --git a/src/compiler/nir/nir_opcodes.py b/src/compiler/nir/nir_opcodes.py
>> index 2375309aca6..032168bae49 100644
>> --- a/src/compiler/nir/nir_opcodes.py
>> +++ b/src/compiler/nir/nir_opcodes.py
>> @@ -491,6 +491,10 @@ binop("frem", tfloat, "", "src0 - src1 * truncf(src0 / 
>> src1)")
>> binop_compare("flt", tfloat, "", "src0 < src1")
>> binop_compare("fge", tfloat, "", "src0 >= src1")
>> binop_compare("feq", tfloat, commutative, "src0 == src1")
>> +binop_compare("fne", tfloat, commutative, "!isnan(src0) && !isnan(src1) && 
>> src0 == src1")
>> +binop_compare("fltu", tfloat, "", "!(src0 >= src1)")
>> +binop_compare("fgeu", tfloat, "", "!(src0 < src1)")
>> +binop_compare("fequ", tfloat, commutative, "isnan(src0) || isnan(src1) || 
>> src0 == src1")
>
> Please add some comment around this that the ones without suffix are
> ordered and the one with u suffix are unordered.

Yeah, I can do that.

> Otherwise
>
>
> Reviewed-by: Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl

Thanks!


>
> for 1-3, 5
>> binop_compare("fneu", tfloat, commutative, "src0 != src1")
>> binop_compare("ilt", tint, "", "src0 < src1")
>> binop_compare("ige", tint, "", "src0 >= src1")
>> diff --git a/src/compiler/nir/nir_opt_algebraic.py 
>> b/src/compiler/nir/nir_opt_algebraic.py
>> index 131d2721934..64327708a66 100644
>> --- a/src/compiler/nir/nir_opt_algebraic.py
>> +++ b/src/compiler/nir/nir_opt_algebraic.py
>> @@ -164,6 +164,11 @@ optimizations = [
>> (('inot', ('ieq', a, b)), ('ine', a, b)),
>> (('inot', ('ine', a, b)), ('ieq', a, b)),
>>
>>
>> +   # Comparison lowering
>> +   (('fltu', a, b), ('inot', ('fge', a, b)), 'options->lower_fltu'),
>> +   (('fgeu', a, b), ('inot', ('flt', a, b)), 'options->lower_fgeu'),
>> +   (('fne', a, b), ('inot', ('fequ', a, b)), 'options->lower_fne_to_fequ'),
>> +
>> # 0.0 >= b2f(a)
>> # b2f(a) <= 0.0
>> # b2f(a) == 0.0 because b2f(a) can only be 0 or 1
>> --
>> 2.19.1
>>
>>
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