r600g/llvm: Fix alpha_to_one piglit tests

Reviewed-by: Tom Stellard <thomas.stellard at amd.com>

src/gallium/drivers/r600/r600_llvm.c

@@ -234,6 +234,8 @@ static void llvm_emit_epilogue(struct lp_build_tgsi_context * bld_base)
 			elements[chan] = LLVMBuildLoad(base->gallivm->builder,
 				ctx->soa.outputs[i][chan], "");
 		}
+		if (ctx->alpha_to_one && ctx->type == TGSI_PROCESSOR_FRAGMENT && ctx->r600_outputs[i].name == TGSI_SEMANTIC_COLOR)
+			elements[3] = lp_build_const_float(base->gallivm, 1.0f);
 		LLVMValueRef output = lp_build_gather_values(base->gallivm, elements, 4);
 
 		if (ctx->type == TGSI_PROCESSOR_VERTEX) {

src/gallium/drivers/r600/r600_shader.c

@@ -1428,6 +1428,7 @@ static int r600_shader_from_tgsi(struct r600_screen *rscreen,
 		radeon_llvm_ctx.fs_color_all = shader->fs_write_all && (rscreen->chip_class >= EVERGREEN);
 		radeon_llvm_ctx.stream_outputs = &so;
 		radeon_llvm_ctx.clip_vertex = ctx.cv_output;
+		radeon_llvm_ctx.alpha_to_one = key.alpha_to_one;
 		mod = r600_tgsi_llvm(&radeon_llvm_ctx, tokens);
 		if (debug_get_bool_option("R600_DUMP_SHADERS", FALSE)) {
 			dump = 1;

src/gallium/drivers/radeon/radeon_llvm.h

@@ -64,6 +64,7 @@ struct radeon_llvm_context {
 	struct pipe_stream_output_info *stream_outputs;
 	unsigned color_buffer_count;
 	unsigned fs_color_all;
+	unsigned alpha_to_one;
 
 	/*=== Front end configuration ===*/