From 801c209fa0a2878c0675b7808154de93bc42f5fd Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Wed, 10 Mar 2021 13:05:41 +0200
Subject: [PATCH] Count EmitVertex as referencing all active outputs

---
 source/glsl/optimize.cpp                      |  7 ++
 .../glsl/conditional_multiple_emitvertex.glsl | 76 +++++++++++++++++++
 2 files changed, 83 insertions(+)
 create mode 100644 tests/glsl/conditional_multiple_emitvertex.glsl

diff --git a/source/glsl/optimize.cpp b/source/glsl/optimize.cpp
index 080bfd7c..441a73a0 100644
--- a/source/glsl/optimize.cpp
+++ b/source/glsl/optimize.cpp
@@ -728,6 +728,13 @@ void UnusedVariableRemover::visit(FunctionCall &call)
 	/* Treat function calls as having side effects so expression statements
 	consisting of nothing but a function call won't be optimized away. */
 	r_side_effects = true;
+
+	if(stage->type==Stage::GEOMETRY && call.name=="EmitVertex")
+	{
+		for(map<Statement *, VariableInfo>::const_iterator i=variables.begin(); i!=variables.end(); ++i)
+			if(i->second.output)
+				referenced(i->first, call);
+	}
 }
 
 void UnusedVariableRemover::record_assignment(const Assignment::Target &target, Node &node)
diff --git a/tests/glsl/conditional_multiple_emitvertex.glsl b/tests/glsl/conditional_multiple_emitvertex.glsl
new file mode 100644
index 00000000..09bf25d1
--- /dev/null
+++ b/tests/glsl/conditional_multiple_emitvertex.glsl
@@ -0,0 +1,76 @@
+uniform bool flag;
+uniform sampler2D tex;
+
+#pragma MSP stage(vertex)
+layout(location=0) in vec4 position;
+void main()
+{
+	out vec2 texcoord = position.xy*0.5+0.5;
+	gl_Position = position;
+}
+
+#pragma MSP stage(geometry)
+layout(triangles) in;
+layout(triangles, max_vertices=3) out;
+void main()
+{
+	passthrough[0];
+	if(flag)
+		EmitVertex();
+	passthrough[1];
+	if(flag)
+		EmitVertex();
+	passthrough[2];
+	if(flag)
+		EmitVertex();
+}
+
+#pragma MSP stage(fragment)
+layout(location=0) out vec4 frag_color;
+void main()
+{
+	frag_color = texture(tex, texcoord);
+}
+
+/* Expected output: vertex
+layout(location=0) in vec4 position;
+out vec2 texcoord;
+void main()
+{
+	texcoord = position.xy*0.5+0.5;
+	gl_Position = position;
+}
+*/
+
+/* Expected output: geometry
+uniform bool flag;
+layout(triangles) in;
+layout(triangles, max_vertices=3) out;
+in vec2 texcoord[];
+out vec2 _gs_out_texcoord;
+void main()
+{
+	gl_Position = gl_in[0].gl_Position;
+	_gs_out_texcoord = texcoord[0];
+	if(flag)
+		EmitVertex();
+	gl_Position = gl_in[1].gl_Position;
+	_gs_out_texcoord = texcoord[1];
+	if(flag)
+		EmitVertex();
+	gl_Position = gl_in[2].gl_Position;
+	_gs_out_texcoord = texcoord[2];
+	if(flag)
+		EmitVertex();
+}
+*/
+
+/* Expected output: fragment
+uniform sampler2D tex;
+layout(location=0) out vec4 frag_color;
+in vec2 _gs_out_texcoord;
+void main()
+{
+	frag_color = texture(tex, _gs_out_texcoord);
+}
+*/
-- 
2.43.0