MSL: Deal with padded fragment output + Component decoration.

reference/shaders-msl-no-opt/components/fragment-output-component.pad-fragment.frag

@@ -0,0 +1,22 @@
+#include <metal_stdlib>
+#include <simd/simd.h>
+
+using namespace metal;
+
+struct main0_out
+{
+    float4 FragColor0 [[color(0)]];
+};
+
+fragment main0_out main0()
+{
+    main0_out out = {};
+    float FragColor0 = {};
+    float2 FragColor1 = {};
+    FragColor0 = 1.0;
+    FragColor1 = float2(2.0, 3.0);
+    out.FragColor0.x = FragColor0;
+    out.FragColor0.yz = FragColor1;
+    return out;
+}
+

shaders-msl-no-opt/components/fragment-output-component.pad-fragment.frag

@@ -0,0 +1,10 @@
+#version 450
+
+layout(location = 0, component = 0) out float FragColor0;
+layout(location = 0, component = 1) out vec2 FragColor1;
+
+void main()
+{
+	FragColor0 = 1.0;
+	FragColor1 = vec2(2.0, 3.0);
+}

spirv_msl.cpp

@@ -1487,25 +1487,19 @@ void CompilerMSL::add_plain_variable_to_interface_block(StorageClass storage, co
 			location_meta = &location_meta_itr->second;
 	}
 
-	// Check if we need to pad fragment output to match a certain number of components.
+	bool pad_fragment_output = has_decoration(var.self, DecorationLocation) && msl_options.pad_fragment_output_components &&
-	if (get_decoration_bitset(var.self).get(DecorationLocation) && msl_options.pad_fragment_output_components &&
+	                           get_entry_point().model == ExecutionModelFragment && storage == StorageClassOutput;
-	    get_entry_point().model == ExecutionModelFragment && storage == StorageClassOutput)
-	{
-		assert(!location_meta);
-		uint32_t locn = get_decoration(var.self, DecorationLocation);
-		target_components = get_target_components_for_fragment_location(locn);
-		if (type_components < target_components)
-		{
-			// Make a new type here.
-			type_id = build_extended_vector_type(type_id, target_components);
-			padded_output = true;
-		}
-	}
 
+	// Check if we need to pad fragment output to match a certain number of components.
 	if (location_meta)
 	{
 		start_component = get_decoration(var.self, DecorationComponent);
 		uint32_t num_components = location_meta->num_components;
+		if (pad_fragment_output)
+		{
+			uint32_t locn = get_decoration(var.self, DecorationLocation);
+			num_components = std::max(num_components, get_target_components_for_fragment_location(locn));
+		}
 
 		if (location_meta->ib_index != ~0u)
 		{
@@ -1542,6 +1536,17 @@ void CompilerMSL::add_plain_variable_to_interface_block(StorageClass storage, co
 				padded_output = true;
 		}
 	}
+	else if (pad_fragment_output)
+	{
+		uint32_t locn = get_decoration(var.self, DecorationLocation);
+		target_components = get_target_components_for_fragment_location(locn);
+		if (type_components < target_components)
+		{
+			// Make a new type here.
+			type_id = build_extended_vector_type(type_id, target_components);
+			padded_output = true;
+		}
+	}
 
 	ib_type.member_types.push_back(type_id);