Reviewed-by: Jason Ekstrand <jason.ekstr...@intel.com>
On Tue, Jan 5, 2016 at 4:25 PM, Kenneth Graunke <kenn...@whitecape.org>
wrote:
> The nir_opt_algebraic rule
>
> (('fadd', ('flog2', a), ('fneg', ('flog2', b))), ('flog2', ('fdiv', a,
> b))),
>
> can produce new fdiv operations, which need to be lowered on i965,
> as we don't actually implement fdiv. (Normally, we handle this in
> GLSL IR's lower_instructions pass, but in the above case we introduce
> an fdiv after that point. So, make NIR do it for us.)
>
> Signed-off-by: Kenneth Graunke <kenn...@whitecape.org>
> Cc: mesa-sta...@lists.freedesktop.org
> ---
> src/glsl/nir/nir.h | 1 +
> src/glsl/nir/nir_opt_algebraic.py | 1 +
> src/mesa/drivers/dri/i965/brw_shader.cpp | 1 +
> 3 files changed, 3 insertions(+)
>
> diff --git a/src/glsl/nir/nir.h b/src/glsl/nir/nir.h
> index 4286738..fed8a97 100644
> --- a/src/glsl/nir/nir.h
> +++ b/src/glsl/nir/nir.h
> @@ -1440,6 +1440,7 @@ typedef struct nir_function {
> } nir_function;
>
> typedef struct nir_shader_compiler_options {
> + bool lower_fdiv;
> bool lower_ffma;
> bool lower_flrp;
> bool lower_fpow;
> diff --git a/src/glsl/nir/nir_opt_algebraic.py
> b/src/glsl/nir/nir_opt_algebraic.py
> index 1fdad3d..c553de5 100644
> --- a/src/glsl/nir/nir_opt_algebraic.py
> +++ b/src/glsl/nir/nir_opt_algebraic.py
> @@ -183,6 +183,7 @@ optimizations = [
> (('fmul', ('fexp2', a), ('fexp2', b)), ('fexp2', ('fadd', a, b))),
> # Division and reciprocal
> (('fdiv', 1.0, a), ('frcp', a)),
> + (('fdiv', a, b), ('fmul', a, ('frcp', b)), 'options->lower_fdiv'),
> (('frcp', ('frcp', a)), a),
> (('frcp', ('fsqrt', a)), ('frsq', a)),
> (('fsqrt', a), ('frcp', ('frsq', a)), 'options->lower_fsqrt'),
> diff --git a/src/mesa/drivers/dri/i965/brw_shader.cpp
> b/src/mesa/drivers/dri/i965/brw_shader.cpp
> index d4b6410..4bd24a7 100644
> --- a/src/mesa/drivers/dri/i965/brw_shader.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_shader.cpp
> @@ -97,6 +97,7 @@ brw_compiler_create(void *mem_ctx, const struct
> brw_device_info *devinfo)
> nir_shader_compiler_options *nir_options =
> rzalloc(compiler, nir_shader_compiler_options);
> nir_options->native_integers = true;
> + nir_options->lower_fdiv = true;
> /* In order to help allow for better CSE at the NIR level we tell NIR
> * to split all ffma instructions during opt_algebraic and we then
> * re-combine them as a later step.
> --
> 2.6.4
>
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> mesa-dev@lists.freedesktop.org
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>
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