[Mesa-dev] [PATCH 2/4] radeonsi: Set range metadata on calls to llvm.SI.tid

[Michael Schellenberger Costa]

Hi Tom,

Am 19.04.2016 um 19:52 schrieb Tom Stellard:
> The range metadata tells LLVM the range of expected values for this intrinsic,
> so it can do some additional optimizations on the result.
> ---
>  src/gallium/drivers/radeonsi/si_shader.c | 29 ++++++++++++++++++++++++++---
>  1 file changed, 26 insertions(+), 3 deletions(-)
>
> diff --git a/src/gallium/drivers/radeonsi/si_shader.c b/src/gallium/drivers/radeonsi/si_shader.c
> index 3b6d6e9..b4f2a42 100644
> --- a/src/gallium/drivers/radeonsi/si_shader.c
> +++ b/src/gallium/drivers/radeonsi/si_shader.c
> @@ -1114,12 +1114,35 @@ static LLVMValueRef get_sample_id(struct radeon_llvm_context *radeon_bld)
>  			    SI_PARAM_ANCILLARY, 8, 4);
>  }
>  
> +/**
> + * Set range metadata on an instruction.  This can only be used on load and
> + * call instructions.  To specify an instruciton can only produce the values
> + * 0, 1, 2, you would do set_range_metadata(value, 0, 3);
> + * \p lo is the minimum value inclusive.
> + * \p hi is the maximum value exclusive.
> + */
> +static void set_range_metadata(LLVMValueRef value, unsigned lo, unsigned hi)
> +{
> +	const char *range_md_string = "range";
> +	LLVMValueRef range_md, md_args[2];
> +	LLVMTypeRef type = LLVMTypeOf(value);
> +	LLVMContextRef context = LLVMGetTypeContext(type);
> +	unsigned md_range_id = LLVMGetMDKindIDInContext(context,
> +				range_md_string, strlen(range_md_string));
> +
> +	md_args[0] = LLVMConstInt(type, lo, false);
> +	md_args[1] = LLVMConstInt(type, hi, false);
> +	range_md = LLVMMDNodeInContext(context, md_args, 2);
> +	LLVMSetMetadata(value, md_range_id, range_md);
> +}
> +
>  static LLVMValueRef get_thread_id(struct si_shader_context *ctx)
>  {
>  	struct gallivm_state *gallivm = &ctx->radeon_bld.gallivm;
> -
> -	return lp_build_intrinsic(gallivm->builder, "llvm.SI.tid", ctx->i32,
> -					   NULL, 0, LLVMReadNoneAttribute);
> +	LLVMValueRef tid = lp_build_intrinsic(gallivm->builder, "llvm.SI.tid",
> +				ctx->i32,   NULL, 0, LLVMReadNoneAttribute);

same here, why not use the helper from patch 1?
Michael
> +	set_range_metadata(tid, 0, 64);
> +	return tid;
>  }
>  
>  /**