[Mesa-dev] [PATCH 6/6] nir: Rework conversion opcodes

[Eric Anholt]

Jason Ekstrand <jason at jlekstrand.net> writes:

> The NIR story on conversion opcodes is a mess.  We've had way too many
> of them, naming is inconsistent, and which ones have explicit sizes was
> sort-of random.  This commit re-organizes things and makes them all
> consistent:
>
>  - All non-bool conversion opcodes now have the explicit size in the
>    destination and are named <src_type>2<dst_type><size>.
>
>  - Integer <-> integer conversion opcodes now only come in i2i and u2u
>    forms (i2u and u2i have been removed) since the only difference
>    between the different integer conversions is whether or not they
>    sign-extend when up-converting.
>
>  - Boolean conversion opcodes all have the explicit size on the bool and
>    are named <src_type>2<dst_type>.
>
> Making things consistent also allows nir_type_conversion_op to be moved
> to nir_opcodes.c and auto-generated using mako.  This will make adding
> int8, int16, and float16 versions much easier when the time comes.
> ---

> diff --git a/src/compiler/nir/nir_opcodes.py b/src/compiler/nir/nir_opcodes.py
> index b116fcf..f7d7d3b 100644
> --- a/src/compiler/nir/nir_opcodes.py
> +++ b/src/compiler/nir/nir_opcodes.py
> @@ -166,42 +166,26 @@ unop("frsq", tfloat, "bit_size == 64 ? 1.0 / sqrt(src0) : 1.0f / sqrtf(src0)")
>  unop("fsqrt", tfloat, "bit_size == 64 ? sqrt(src0) : sqrtf(src0)")
>  unop("fexp2", tfloat, "exp2f(src0)")
>  unop("flog2", tfloat, "log2f(src0)")
> -unop_convert("f2i", tint32, tfloat32, "src0") # Float-to-integer conversion.
> -unop_convert("f2u", tuint32, tfloat32, "src0") # Float-to-unsigned conversion
> -unop_convert("d2i", tint32, tfloat64, "src0") # Double-to-integer conversion.
> -unop_convert("d2u", tuint32, tfloat64, "src0") # Double-to-unsigned conversion.
> -unop_convert("i2f", tfloat32, tint32, "src0") # Integer-to-float conversion.
> -unop_convert("i2d", tfloat64, tint32, "src0") # Integer-to-double conversion.
> -unop_convert("i2i32", tint32, tint, "src0")    # General int (int8_t, int64_t, etc.) to int32_t conversion
> -unop_convert("u2i32", tint32, tuint, "src0")   # General uint (uint8_t, uint64_t, etc.) to int32_t conversion
> -unop_convert("i2u32", tuint32, tint, "src0")   # General int (int8_t, int64_t, etc.) to uint32_t conversion
> -unop_convert("u2u32", tuint32, tuint, "src0")  # General uint (uint8_t, uint64_t, etc.) to uint32_t conversion
> -unop_convert("i2i64", tint64, tint, "src0")    # General int (int8_t, int32_t, etc.) to int64_t conversion
> -unop_convert("u2i64", tint64, tuint, "src0")   # General uint (uint8_t, uint64_t, etc.) to int64_t conversion
> -unop_convert("f2i64", tint64, tfloat, "src0")  # General float (float or double) to int64_t conversion
> -unop_convert("i2u64", tuint64, tint,  "src0")  # General int (int8_t, int64_t, etc.) to uint64_t conversion
> -unop_convert("u2u64", tuint64, tuint, "src0")  # General uint (uint8_t, uint32_t, etc.) to uint64_t conversion
> -unop_convert("f2u64", tuint64, tfloat, "src0") # General float (float or double) to uint64_t conversion
> -unop_convert("i642f", tfloat32, tint64, "src0")  # int64_t-to-float conversion.
> -unop_convert("i642b", tbool, tint64, "src0")  # int64_t-to-bool conversion.
> -unop_convert("i642d", tfloat64, tint64, "src0")  # int64_t-to-double conversion.
> -unop_convert("u642f", tfloat32, tuint64, "src0") # uint64_t-to-float conversion.
> -unop_convert("u642d", tfloat64, tuint64, "src0") # uint64_t-to-double conversion.
> -
> -# Float-to-boolean conversion
> -unop_convert("f2b", tbool, tfloat32, "src0 != 0.0f")
> -unop_convert("d2b", tbool, tfloat64, "src0 != 0.0")
> -# Boolean-to-float conversion
> -unop_convert("b2f", tfloat32, tbool, "src0 ? 1.0f : 0.0f")
> -# Int-to-boolean conversion
> +
> +# Generate all of the numeric conversion opcodes
> +for src_t in [tint, tuint, tfloat, tbool]:
> +   if src_t in (tint, tuint):
> +      dst_types = [tfloat, src_t]
> +   elif src_t == tfloat:
> +      dst_types = [tint, tuint, tfloat]
> +
> +   for dst_t in dst_types:
> +      for bit_size in [32, 64]:
> +         unop_convert("{}2{}{}".format(src_t[0], dst_t[0], bit_size),
> +                      dst_t + str(bit_size), src_t, "src0")
> +
> +# We'll hand-code the to/from bool conversion opcodes.  Because bool doesn't
> +# have multiple bit-sizes, we can always infer the size from the other type.
> +unop_convert("f2b", tbool, tfloat, "src0 != 0.0")
>  unop_convert("i2b", tbool, tint, "src0 != 0")
> -unop_convert("b2i", tint32, tbool, "src0 ? 1 : 0") # Boolean-to-int conversion
> -unop_convert("b2i64", tint64, tbool, "src0 ? 1 : 0")  # Boolean-to-int64_t conversion.
> -unop_convert("u2f", tfloat32, tuint32, "src0") # Unsigned-to-float conversion.
> -unop_convert("u2d", tfloat64, tuint32, "src0") # Unsigned-to-double conversion.
> -# double-to-float conversion
> -unop_convert("d2f", tfloat32, tfloat64, "src0") # Double to single precision
> -unop_convert("f2d", tfloat64, tfloat32, "src0") # Single to double precision
> +unop_convert("b2f", tfloat, tbool, "src0 ? 1.0 : 0.0")
> +unop_convert("b2i", tint, tbool, "src0 ? 1 : 0")

I'm confused.  The loop includes "tbool" in src_t iteration, so that
makes me think it would be generating a unop_convert() for, say, b2i64
(despite the commit message saying bool conversions don't get sizes),
but then there are these hand-written unop_converts for bools here and I
don't see b2i64 in any of the code.

Other than this question, patches 1-3 and 6 are:

Reviewed-by: Eric Anholt <eric at anholt.net>
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