From: Mikko Rasa <tdb@tdb.fi>
Date: Sun, 10 Oct 2021 12:37:07 +0000 (+0300)
Subject: Remove output variables which are not referenced
X-Git-Url: http://git.tdb.fi/?a=commitdiff_plain;h=209fc09bcf2947ca60ddf15b8903d0c3194c7d5d;p=libs%2Fgl.git

Remove output variables which are not referenced
---

diff --git a/source/glsl/optimize.cpp b/source/glsl/optimize.cpp
index a8ff44a5..1e974c9f 100644
--- a/source/glsl/optimize.cpp
+++ b/source/glsl/optimize.cpp
@@ -1260,15 +1260,15 @@ bool UnusedVariableRemover::apply(Stage &s)
 
 	for(const auto &kvp: variables)
 	{
-		if(kvp.second.output)
+		if(!kvp.second.referenced)
+			unused_nodes.insert(kvp.first);
+		else if(kvp.second.output)
 		{
 			/* The last visible assignments of output variables are used by the
 			next stage or the API. */
 			for(AssignmentInfo *a: kvp.second.assignments)
 				unused_nodes.erase(a->node);
 		}
-		else if(!kvp.second.referenced)
-			unused_nodes.insert(kvp.first);
 	}
 
 	NodeRemover().apply(s, unused_nodes);
@@ -1490,6 +1490,10 @@ void UnusedVariableRemover::visit(VariableDeclaration &var)
 	graphics API. */
 	var_info.output = (var.interface=="out" && (stage->type==Stage::FRAGMENT || var.linked_declaration || !var.name.compare(0, 3, "gl_")));
 
+	// Linked outputs are automatically referenced.
+	if(var_info.output && var.linked_declaration)
+		var_info.referenced = true;
+
 	if(var.init_expression)
 	{
 		var_info.initialized = true;