From: Mikko Rasa <tdb@tdb.fi>
Date: Tue, 6 Apr 2021 09:48:44 +0000 (+0300)
Subject: Leave no-op constructors as they are
X-Git-Url: http://git.tdb.fi/?p=libs%2Fgl.git;a=commitdiff_plain;h=fe7996a5985e8e7064004d2f42758d89ebf54b57

Leave no-op constructors as they are

In particular, don't break a matrix down into columns and construct
it again.  These could just be removed from the AST entirely, but the
expression resolver currently does not do node replacement and it's
easier to just skip this in the backend.
---

diff --git a/source/glsl/resolve.cpp b/source/glsl/resolve.cpp
index 3201ea1b..2b18c84b 100644
--- a/source/glsl/resolve.cpp
+++ b/source/glsl/resolve.cpp
@@ -883,6 +883,8 @@ void ExpressionResolver::visit_constructor(FunctionCall &call)
 	map<string, TypeDeclaration *>::const_iterator i = stage->types.find(call.name);
 	if(i==stage->types.end())
 		return;
+	else if(call.arguments.size()==1 && i->second==call.arguments[0]->type)
+		;
 	else if(BasicTypeDeclaration *basic = dynamic_cast<BasicTypeDeclaration *>(i->second))
 	{
 		BasicTypeDeclaration *elem = get_element_type(*basic);
diff --git a/tests/glsl/no_op_conversion.glsl b/tests/glsl/no_op_conversion.glsl
new file mode 100644
index 00000000..2e3ff57b
--- /dev/null
+++ b/tests/glsl/no_op_conversion.glsl
@@ -0,0 +1,17 @@
+uniform mat4 mvp;
+
+#pragma MSP stage(vertex)
+layout(location=0) in vec4 position;
+int main()
+{
+	gl_Position = mat4(mvp)*vec4(position);
+}
+
+/* Expected output: vertex
+layout(location=0) uniform mat4 mvp;
+layout(location=0) in vec4 position;
+int main()
+{
+  gl_Position = mat4(mvp)*vec4(position);
+}
+*/