From 31f76e306f8e01884fa464ac6e09e8b48af5f79b Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Mon, 8 Nov 2021 02:09:11 +0200
Subject: [PATCH] Block further inlining of a variable after component
 assignment

---
 source/glsl/optimize.cpp          | 12 ++++++++----
 source/glsl/optimize.h            |  1 +
 tests/glsl/member_assignment.glsl |  6 ++----
 3 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/source/glsl/optimize.cpp b/source/glsl/optimize.cpp
index a7f29a16..c9d3c33a 100644
--- a/source/glsl/optimize.cpp
+++ b/source/glsl/optimize.cpp
@@ -356,7 +356,7 @@ void ExpressionInliner::visit(RefPtr<Expression> &expr)
 		ExpressionUse use;
 		use.reference = &expr;
 		use.ref_scope = current_block;
-		use.blocked = access_write;
+		use.blocked = access_write || r_ref_info->blocked;
 
 		if(iteration_body && !r_ref_info->trivial)
 		{
@@ -428,10 +428,10 @@ void ExpressionInliner::visit(Assignment &assign)
 	r_trivial = true;
 	visit(assign.right);
 
-	auto i = assignments.find(assign.target);
+	auto i = assignments.find(assign.target.declaration);
 	if(i!=assignments.end())
 	{
-		if(iteration_body && i->second->expression)
+		if(iteration_body && i->second && i->second->expression)
 		{
 			/* Block inlining into previous references within the iteration
 			statement.  On iterations after the first they would refer to the
@@ -441,6 +441,10 @@ void ExpressionInliner::visit(Assignment &assign)
 					u.blocked = (k==iteration_body);
 		}
 
+		for(; (i!=assignments.end() && i->first.declaration==assign.target.declaration); ++i)
+			if(targets_overlap(i->first, assign.target))
+				i->second->blocked = true;
+
 		expressions.push_back(ExpressionInfo());
 		ExpressionInfo &info = expressions.back();
 		info.target = assign.target;
@@ -450,7 +454,7 @@ void ExpressionInliner::visit(Assignment &assign)
 		info.assign_scope = current_block;
 		info.trivial = r_trivial;
 
-		i->second = &info;
+		assignments[assign.target] = &info;
 	}
 
 	r_trivial = false;
diff --git a/source/glsl/optimize.h b/source/glsl/optimize.h
index 9b7b7aff..82fc78cc 100644
--- a/source/glsl/optimize.h
+++ b/source/glsl/optimize.h
@@ -122,6 +122,7 @@ private:
 		Block *assign_scope = 0;
 		std::vector<ExpressionUse> uses;
 		bool trivial = false;
+		bool blocked = false;
 	};
 
 	std::list<ExpressionInfo> expressions;
diff --git a/tests/glsl/member_assignment.glsl b/tests/glsl/member_assignment.glsl
index 8444cfca..77451db0 100644
--- a/tests/glsl/member_assignment.glsl
+++ b/tests/glsl/member_assignment.glsl
@@ -1,9 +1,8 @@
 #pragma MSP stage(vertex)
 void main()
 {
-	vec4 p;
+	vec4 p = vec4(0.0);
 	p.x = 1.0;
-	p.y = 0.0;
 	p.z = 2.0;
 	p.w = 1.0;
 	gl_Position = p;
@@ -12,9 +11,8 @@ void main()
 /* Expected output: vertex
 void main()
 {
-	vec4 p;
+	vec4 p = vec4(0.0);
 	p.x = 1.0;
-	p.y = 0.0;
 	p.z = 2.0;
 	p.w = 1.0;
 	gl_Position = p;
-- 
2.43.0