[Mesa-dev] [PATCH 3/4] radeonsi: Use llvm.amdgcn.mbcnt.* intrinsics instead of llvm.SI.tid v2

[Michael Schellenberger Costa]

Hi Tom

Am 19.04.2016 um 19:52 schrieb Tom Stellard:
> We're trying to move to more of the new style intrinsics with include
> the correct target name, and map directly to ISA instructions.
>
> v2:
>   - Only do this with LLVM 3.8 and newer.
> ---
>  src/gallium/drivers/radeonsi/si_shader.c | 17 ++++++++++++++++-
>  1 file changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
> index b4f2a42..2a747f9 100644
> --- a/src/gallium/drivers/radeonsi/si_shader.c
> +++ b/src/gallium/drivers/radeonsi/si_shader.c
> @@ -1139,8 +1139,23 @@ static void set_range_metadata(LLVMValueRef value, unsigned lo, unsigned hi)
>  static LLVMValueRef get_thread_id(struct si_shader_context *ctx)
>  {
>  	struct gallivm_state *gallivm = &ctx->radeon_bld.gallivm;
> -	LLVMValueRef tid = lp_build_intrinsic(gallivm->builder, "llvm.SI.tid",
> +	LLVMValueRef tid;
> +
> +	if (HAVE_LLVM < 0x0308) {
> +		tid = lp_build_intrinsic(gallivm->builder, "llvm.SI.tid",
>  				ctx->i32,   NULL, 0, LLVMReadNoneAttribute);
Is there a reason not to use the helper from patch 1?
Michael
> +	} else {
> +		LLVMValueRef tid_args[2];
> +		tid_args[0] = lp_build_const_int32(gallivm, 0xffffffff);
> +		tid_args[1] = lp_build_const_int32(gallivm, 0);
> +		tid_args[1] = lp_build_intrinsic(gallivm->builder,
> +					"llvm.amdgcn.mbcnt.lo", ctx->i32,
> +					tid_args, 2, LLVMReadNoneAttribute);
> +
> +		tid = lp_build_intrinsic(gallivm->builder,
> +					"llvm.amdgcn.mbcnt.hi", ctx->i32,
> +					tid_args, 2, LLVMReadNoneAttribute);
> +	}
>  	set_range_metadata(tid, 0, 64);
>  	return tid;
>  }