Since you acked patch #3, which depends on this, I assume this has your Rb too?
Marek
On Mon, Mar 2, 2015 at 10:05 PM, Tom Stellard <t...@stellard.net> wrote:
> 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
>>
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