[Mesa-dev] [PATCH 1/3] radeon/ac: add emit umsb shared code.

[Edward O'Callaghan]

This series is,
Reviewed-by: Edward O'Callaghan <funfunctor at folklore1984.net>

On 02/16/2017 02:55 PM, Dave Airlie wrote:
> From: Dave Airlie <airlied at redhat.com>
> 
> Since we shared imsb, makes sense to share umsb.
> 
> Signed-off-by: Dave Airlie <airlied at redhat.com>
> ---
>  src/amd/common/ac_llvm_build.c | 25 +++++++++++++++++++++++++
>  src/amd/common/ac_llvm_build.h |  4 ++++
>  2 files changed, 29 insertions(+)
> 
> diff --git a/src/amd/common/ac_llvm_build.c b/src/amd/common/ac_llvm_build.c
> index dda2c0b..ed31a56 100644
> --- a/src/amd/common/ac_llvm_build.c
> +++ b/src/amd/common/ac_llvm_build.c
> @@ -788,3 +788,28 @@ ac_emit_imsb(struct ac_llvm_context *ctx,
>  
>  	return LLVMBuildSelect(ctx->builder, cond, all_ones, msb, "");
>  }
> +
> +LLVMValueRef
> +ac_emit_umsb(struct ac_llvm_context *ctx,
> +	     LLVMValueRef arg,
> +	     LLVMTypeRef dst_type)
> +{
> +	LLVMValueRef args[2] = {
> +		arg,
> +		LLVMConstInt(ctx->i32, 1, 0),
> +	};
> +	LLVMValueRef msb = ac_emit_llvm_intrinsic(ctx, "llvm.ctlz.i32",
> +						  dst_type, args, ARRAY_SIZE(args),
> +						  AC_FUNC_ATTR_READNONE);
> +
> +	/* The HW returns the last bit index from MSB, but TGSI/NIR wants
> +	 * the index from LSB. Invert it by doing "31 - msb". */
> +	msb = LLVMBuildSub(ctx->builder, LLVMConstInt(ctx->i32, 31, false),
> +			   msb, "");
> +
> +	/* check for zero */
> +	return LLVMBuildSelect(ctx->builder,
> +			       LLVMBuildICmp(ctx->builder, LLVMIntEQ, arg,
> +					     LLVMConstInt(ctx->i32, 0, 0), ""),
> +			       LLVMConstInt(ctx->i32, -1, true), msb, "");
> +}
> diff --git a/src/amd/common/ac_llvm_build.h b/src/amd/common/ac_llvm_build.h
> index 0ff04e4..3258e5e 100644
> --- a/src/amd/common/ac_llvm_build.h
> +++ b/src/amd/common/ac_llvm_build.h
> @@ -186,6 +186,10 @@ LLVMValueRef ac_emit_imsb(struct ac_llvm_context *ctx,
>  			  LLVMValueRef arg,
>  			  LLVMTypeRef dst_type);
>  
> +LLVMValueRef ac_emit_umsb(struct ac_llvm_context *ctx,
> +			  LLVMValueRef arg,
> +			  LLVMTypeRef dst_type);
> +
>  #ifdef __cplusplus
>  }
>  #endif
> 

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