[Mesa-dev] [PATCH 2/3] r600g: use fdiv instruction for TGSI_OPCODE_DIV/RCP

[Tom Stellard]

On Thu, Nov 29, 2012 at 09:32:08PM +0100, Vincent Lejeune wrote:
> ---
>  src/gallium/drivers/r600/r600_llvm.c               | 22 ++++++++++++++++++++++
>  .../drivers/radeon/radeon_setup_tgsi_llvm.c        |  4 ++--
>  2 files changed, 24 insertions(+), 2 deletions(-)
> 
> diff --git a/src/gallium/drivers/r600/r600_llvm.c b/src/gallium/drivers/r600/r600_llvm.c
> index 350527b..2056b91 100644
> --- a/src/gallium/drivers/r600/r600_llvm.c
> +++ b/src/gallium/drivers/r600/r600_llvm.c
> @@ -408,6 +408,26 @@ static void llvm_fmad(
>  		emit_data->args[2], "");
>  }
>  
> +static void llvm_fdiv(
> +const struct lp_build_tgsi_action * action,
> +struct lp_build_tgsi_context * bld_base,
> +struct lp_build_emit_data * emit_data)
> +{
> +	LLVMBuilderRef builder = bld_base->base.gallivm->builder;
> +	emit_data->output[emit_data->chan] = LLVMBuildFDiv(builder,
> +		emit_data->args[0], emit_data->args[1], "");
> +}
> +
> +static void llvm_frcp(
> +const struct lp_build_tgsi_action * action,
> +struct lp_build_tgsi_context * bld_base,
> +struct lp_build_emit_data * emit_data)
> +{
> +	LLVMBuilderRef builder = bld_base->base.gallivm->builder;
> +	emit_data->output[emit_data->chan] = LLVMBuildFDiv(builder,
> +		lp_build_const_float(bld_base->base.gallivm, 1.0f), emit_data->args[0], "");
> +}
> +

I think we should move these implementations into lp_bld_tgsi_action.c,
since they are generic.

>  static struct lp_build_tgsi_action dot_action = {
>  	.fetch_args = dp_fetch_args,
>  	.emit = build_tgsi_intrinsic_nomem,
> @@ -451,6 +471,8 @@ LLVMModuleRef r600_tgsi_llvm(
>  	bld_base->op_actions[TGSI_OPCODE_CMP].emit = emit_cndlt;
>  	bld_base->op_actions[TGSI_OPCODE_MUL].emit = llvm_fmul;
>  	bld_base->op_actions[TGSI_OPCODE_MAD].emit = llvm_fmad;
> +	bld_base->op_actions[TGSI_OPCODE_DIV].emit = llvm_fdiv;
> +	bld_base->op_actions[TGSI_OPCODE_RCP].emit = llvm_frcp;
>  
>  	lp_build_tgsi_llvm(bld_base, tokens);
>  
> diff --git a/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c b/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c
> index cbcebbc..93d3009 100644
> --- a/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c
> +++ b/src/gallium/drivers/radeon/radeon_setup_tgsi_llvm.c
> @@ -540,8 +540,8 @@ static void emit_prepare_cube_coords(
>  
>  	coords[2] = build_intrinsic(builder, "fabs",
>  			type, &coords[2], 1, LLVMReadNoneAttribute);
> -	coords[2] = build_intrinsic(builder, "llvm.AMDGPU.rcp",
> -			type, &coords[2], 1, LLVMReadNoneAttribute);
> +	coords[2] = LLVMBuildFDiv(builder, lp_build_const_float(gallivm, 1.0f),
> +			coords[2], "");
>  

We can use the lp_build_emit_llvm_unary() helper function here and pass it the
RCP opcode.


>  	mad_args[1] = coords[2];
>  	mad_args[2] = LLVMConstReal(type, 1.5);
> -- 
> 1.8.0
> 
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