vk/gl: Mark unused FP outputs as unused

rpcs3/Emu/RSX/GL/GLFragmentProgram.cpp

@@ -103,7 +103,18 @@ void GLFragmentDecompilerThread::insertOutputs(std::stringstream & OS)
 	const auto reg_type = float_type ? "vec4" : getHalfTypeName(4);
 	for (uint i = 0; i < std::size(table); ++i)
 	{
-		if (m_parr.HasParam(PF_PARAM_NONE, reg_type, table[i].second))
+		if (!m_parr.HasParam(PF_PARAM_NONE, reg_type, table[i].second))
+		{
+			continue;
+		}
+
+		if (i >= m_prog.mrt_buffers_count)
+		{
+			// Dead writes. Declare as temp variables for DCE to clean up.
+			OS << "vec4 " << table[i].first << "; // Unused\n";
+			continue;
+		}
+
 		OS << "layout(location=" << i << ") out vec4 " << table[i].first << ";\n";
 	}
 }

rpcs3/Emu/RSX/VK/VKFragmentProgram.cpp

@@ -156,13 +156,23 @@ void VKFragmentDecompilerThread::insertOutputs(std::stringstream & OS)
 	const auto reg_type = float_type ? "vec4" : getHalfTypeName(4);
 	for (uint i = 0; i < std::size(table); ++i)
 	{
-		if (m_parr.HasParam(PF_PARAM_NONE, reg_type, table[i].second))
+		if (!m_parr.HasParam(PF_PARAM_NONE, reg_type, table[i].second))
 		{
+			continue;
+		}
+
+		if (i >= m_prog.mrt_buffers_count)
+		{
+			// Dead writes. Declare as temp variables for DCE to clean up.
+			OS << "vec4 " << table[i].first << "; // Unused\n";
+			vk_prog->output_color_masks[i] = 0;
+			continue;
+		}
+
 		OS << "layout(location=" << std::to_string(output_index++) << ") " << "out vec4 " << table[i].first << ";\n";
 		vk_prog->output_color_masks[i] = -1;
 	}
 }
-}
 
 void VKFragmentDecompilerThread::insertConstants(std::stringstream & OS)
 {