[Mesa-dev] [PATCH 7.5/11] glsl: Kill __intrinsic_atomic_sub

[Ilia Mirkin]

On Thu, Jul 7, 2016 at 5:02 PM, Ian Romanick <idr at freedesktop.org> wrote:
> From: Ian Romanick <ian.d.romanick at intel.com>
>
> Just generate an __intrinsic_atomic_add with a negated parameter.
>
> Signed-off-by: Ian Romanick <ian.d.romanick at intel.com>
> ---
>  src/compiler/glsl/builtin_functions.cpp    | 50 +++++++++++++++++++++++++++---
>  src/mesa/state_tracker/st_glsl_to_tgsi.cpp |  8 -----
>  2 files changed, 46 insertions(+), 12 deletions(-)
>
> diff --git a/src/compiler/glsl/builtin_functions.cpp b/src/compiler/glsl/builtin_functions.cpp
> index 941ea12..ef3b2b0 100644
> --- a/src/compiler/glsl/builtin_functions.cpp
> +++ b/src/compiler/glsl/builtin_functions.cpp
> @@ -3310,13 +3310,29 @@ builtin_builder::asin_expr(ir_variable *x, float p0, float p1)
>                                            mul(abs(x), imm(p1))))))))));
>  }
>
> +/**
> + * Generate a ir_call to a function with a set of parameters
> + *
> + * The input \c params can either be a list of \c ir_variable or a list of
> + * \c ir_dereference_variable.  In the latter case, all nodes will be removed
> + * from \c params and used directly as the parameters to the generated
> + * \c ir_call.
> + */
>  ir_call *
>  builtin_builder::call(ir_function *f, ir_variable *ret, exec_list params)
>  {
>     exec_list actual_params;
>
> -   foreach_in_list(ir_variable, var, &params) {
> -      actual_params.push_tail(var_ref(var));
> +   foreach_in_list_safe(ir_instruction, ir, &params) {
> +      ir_dereference_variable *d = ir->as_dereference_variable();
> +      if (d != NULL) {
> +         d->remove();
> +         actual_params.push_tail(d);
> +      } else {
> +         ir_variable *var = ir->as_variable();
> +         assert(var != NULL);
> +         actual_params.push_tail(var_ref(var));
> +      }
>     }
>
>     ir_function_signature *sig =
> @@ -5292,8 +5308,34 @@ builtin_builder::_atomic_counter_op1(const char *intrinsic,
>     MAKE_SIG(glsl_type::uint_type, avail, 2, counter, data);
>
>     ir_variable *retval = body.make_temp(glsl_type::uint_type, "atomic_retval");
> -   body.emit(call(shader->symbols->get_function(intrinsic), retval,
> -                  sig->parameters));
> +
> +   /* Instead of generating an __intrinsic_atomic_sub, generate an
> +    * __intrinsic_atomic_add with the data parameter negated.
> +    */
> +   if (strcmp("__intrinsic_atomic_sub", intrinsic) == 0) {
> +      ir_variable *const neg_data =
> +         body.make_temp(glsl_type::uint_type, "neg_data");
> +
> +      body.emit(assign(neg_data, neg(data)));
> +
> +      exec_list parameters;
> +
> +      parameters.push_tail(new(mem_ctx) ir_dereference_variable(counter));
> +      parameters.push_tail(new(mem_ctx) ir_dereference_variable(neg_data));

I don't get it ... why change call() to allow taking dereferences and
create them here rather than just feeding in the ir_variables
directly?

> +
> +      ir_function *const func =
> +         shader->symbols->get_function("__intrinsic_atomic_add");
> +      ir_instruction *const c = call(func, retval, parameters);
> +
> +      assert(c != NULL);
> +      assert(parameters.is_empty());
> +
> +      body.emit(c);
> +   } else {
> +      body.emit(call(shader->symbols->get_function(intrinsic), retval,
> +                     sig->parameters));
> +   }
> +
>     body.emit(ret(retval));
>     return sig;
>  }
> diff --git a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
> index 197b3af..3320f2a 100644
> --- a/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
> +++ b/src/mesa/state_tracker/st_glsl_to_tgsi.cpp
> @@ -3208,13 +3208,6 @@ glsl_to_tgsi_visitor::visit_atomic_counter_intrinsic(ir_call *ir)
>           val = ((ir_instruction *)param)->as_rvalue();
>           val->accept(this);
>           data2 = this->result;
> -      } else if (!strcmp("__intrinsic_atomic_sub", callee)) {
> -         opcode = TGSI_OPCODE_ATOMUADD;
> -         st_src_reg res = get_temp(glsl_type::uvec4_type);
> -         st_dst_reg dstres = st_dst_reg(res);
> -         dstres.writemask = dst.writemask;
> -         emit_asm(ir, TGSI_OPCODE_INEG, dstres, data);
> -         data = res;
>        } else {
>           assert(!"Unexpected intrinsic");
>           return;
> @@ -3625,7 +3618,6 @@ glsl_to_tgsi_visitor::visit(ir_call *ir)
>         !strcmp("__intrinsic_atomic_increment", callee) ||
>         !strcmp("__intrinsic_atomic_predecrement", callee) ||
>         !strcmp("__intrinsic_atomic_add", callee) ||
> -       !strcmp("__intrinsic_atomic_sub", callee) ||
>         !strcmp("__intrinsic_atomic_min", callee) ||
>         !strcmp("__intrinsic_atomic_max", callee) ||
>         !strcmp("__intrinsic_atomic_and", callee) ||
> --
> 2.5.5
>
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