[Mesa-dev] [PATCH 22/59] compiler/nir: add lowering for 16-bit ldexp

[Pohjolainen, Topi]

I remember people preferring to order things 16, 32, 64 before. Should
we follow that here as well?

On Tue, Dec 04, 2018 at 08:16:46AM +0100, Iago Toral Quiroga wrote:
> ---
>  src/compiler/nir/nir_opt_algebraic.py | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/src/compiler/nir/nir_opt_algebraic.py b/src/compiler/nir/nir_opt_algebraic.py
> index 6c3b77c9b6e..747f1751086 100644
> --- a/src/compiler/nir/nir_opt_algebraic.py
> +++ b/src/compiler/nir/nir_opt_algebraic.py
> @@ -778,6 +778,8 @@ def fexp2i(exp, bits):
>        return ('ishl', ('iadd', exp, 127), 23)
>     elif bits == 64:
>        return ('pack_64_2x32_split', 0, ('ishl', ('iadd', exp, 1023), 20))
> +   elif bits == 16:
> +      return ('i2i16', ('ishl', ('iadd', exp, 15), 10))
>     else:
>        assert False
>  
> @@ -796,6 +798,8 @@ def ldexp(f, exp, bits):
>        exp = ('imin', ('imax', exp, -252), 254)
>     elif bits == 64:
>        exp = ('imin', ('imax', exp, -2044), 2046)
> +   elif bits == 16:
> +      exp = ('imin', ('imax', exp, -30), 30)

I expected this to be:

         exp = ('imin', ('imax', exp, -29), 30)

>     else:
>        assert False
>  
> @@ -814,6 +818,7 @@ def ldexp(f, exp, bits):
>  optimizations += [
>     (('ldexp at 32', 'x', 'exp'), ldexp('x', 'exp', 32), 'options->lower_ldexp'),
>     (('ldexp at 64', 'x', 'exp'), ldexp('x', 'exp', 64), 'options->lower_ldexp'),
> +   (('ldexp at 16', 'x', 'exp'), ldexp('x', 'exp', 16), 'options->lower_ldexp'),
>  ]
>  
>  # Unreal Engine 4 demo applications open-codes bitfieldReverse()
> -- 
> 2.17.1
> 
> _______________________________________________
> mesa-dev mailing list
> mesa-dev at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/mesa-dev