On Mon, Mar 02, 2015 at 12:54:16PM +0100, Marek Olšák wrote:
> From: Marek Olšák <marek.ol...@amd.com>
>
> ---
> src/gallium/drivers/radeonsi/si_shader.c | 22 ++++++++++++++++------
> 1 file changed, 16 insertions(+), 6 deletions(-)
>
> diff --git a/src/gallium/drivers/radeonsi/si_shader.c
> b/src/gallium/drivers/radeonsi/si_shader.c
> index b0417ed..f125483 100644
> --- a/src/gallium/drivers/radeonsi/si_shader.c
> +++ b/src/gallium/drivers/radeonsi/si_shader.c
> @@ -192,6 +192,20 @@ static int get_param_index(unsigned semantic_name,
> unsigned index,
> }
>
> /**
> + * BitField Extract: ((value >> rshift) & ((1 << bitwidth) - 1))
> + */
Ideally, we would just add a pattern for this in the backend and emit generic
LLVM IR here. This would also make it possible to share the code with llvmpipe.
I think the best place to do this would be in
AMDGPUTargetLowering::performDAGCombine().
-Tom
> +static LLVMValueRef build_bfe(struct gallivm_state *gallivm,
> + LLVMValueRef value, LLVMValueRef rshift,
> + LLVMValueRef bitwidth)
> +{
> + LLVMValueRef args[3] = {value, rshift, bitwidth};
> +
> + return build_intrinsic(gallivm->builder, "llvm.AMDGPU.bfe.u32",
> + LLVMInt32TypeInContext(gallivm->context),
> + args, Elements(args), LLVMReadNoneAttribute);
> +}
> +
> +/**
> * Build an LLVM bytecode indexed load using LLVMBuildGEP + LLVMBuildLoad.
> * It's equivalent to doing a load from &base_ptr[index].
> *
> @@ -1721,7 +1735,6 @@ static void tex_fetch_args(
>
> /* Initialize some constants. */
> LLVMValueRef four = LLVMConstInt(uint_bld->elem_type, 4, 0);
> - LLVMValueRef F = LLVMConstInt(uint_bld->elem_type, 0xF, 0);
>
> /* Apply the formula. */
> LLVMValueRef fmask =
> @@ -1734,11 +1747,8 @@ static void tex_fetch_args(
> LLVMValueRef sample_index4 =
> LLVMBuildMul(gallivm->builder, address[sample_chan],
> four, "");
>
> - LLVMValueRef shifted_fmask =
> - LLVMBuildLShr(gallivm->builder, fmask, sample_index4,
> "");
> -
> - LLVMValueRef final_sample =
> - LLVMBuildAnd(gallivm->builder, shifted_fmask, F, "");
> + LLVMValueRef final_sample = build_bfe(gallivm, fmask,
> + sample_index4, four);
>
> /* Don't rewrite the sample index if WORD1.DATA_FORMAT of the
> FMASK
> * resource descriptor is 0 (invalid),
> --
> 2.1.0
>
> _______________________________________________
> mesa-dev mailing list
> mesa-dev@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/mesa-dev
_______________________________________________
mesa-dev mailing list
mesa-dev@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/mesa-dev
