X-Git-Url: http://git.tdb.fi/?p=libs%2Fgl.git;a=blobdiff_plain;f=source%2Fglsl%2Foptimize.cpp;h=ed20bb175dcc9277e1ff84e2e1a1734b2279668f;hp=668f7c5ef2553d399feef9c6c60949990fa54150;hb=8bf70f4d445cf63386ad7aafc5b3ebdbd8369939;hpb=d5c38c181cac4da490c96123e5a88a8c06785e55

diff --git a/source/glsl/optimize.cpp b/source/glsl/optimize.cpp
index 668f7c5e..ed20bb17 100644
--- a/source/glsl/optimize.cpp
+++ b/source/glsl/optimize.cpp
@@ -1,6 +1,8 @@
 #include <msp/core/raii.h>
 #include <msp/strings/format.h>
+#include <msp/strings/utils.h>
 #include "optimize.h"
+#include "reflect.h"
 
 using namespace std;
 
@@ -8,6 +10,55 @@ namespace Msp {
 namespace GL {
 namespace SL {
 
+ConstantSpecializer::ConstantSpecializer():
+	values(0)
+{ }
+
+void ConstantSpecializer::apply(Stage &stage, const map<string, int> &v)
+{
+	values = &v;
+	stage.content.visit(*this);
+}
+
+void ConstantSpecializer::visit(VariableDeclaration &var)
+{
+	bool specializable = false;
+	if(var.layout)
+	{
+		vector<Layout::Qualifier> &qualifiers = var.layout->qualifiers;
+		for(vector<Layout::Qualifier>::iterator i=qualifiers.begin(); (!specializable && i!=qualifiers.end()); ++i)
+			if(i->name=="constant_id")
+			{
+				specializable = true;
+				qualifiers.erase(i);
+			}
+
+		if(qualifiers.empty())
+			var.layout = 0;
+	}
+
+	if(specializable)
+	{
+		map<string, int>::const_iterator i = values->find(var.name);
+		if(i!=values->end())
+		{
+			RefPtr<Literal> literal = new Literal;
+			if(var.type=="bool")
+			{
+				literal->token = (i->second ? "true" : "false");
+				literal->value = static_cast<bool>(i->second);
+			}
+			else if(var.type=="int")
+			{
+				literal->token = lexical_cast<string>(i->second);
+				literal->value = i->second;
+			}
+			var.init_expression = literal;
+		}
+	}
+}
+
+
 InlineableFunctionLocator::InlineableFunctionLocator():
 	current_function(0),
 	return_count(0)
@@ -25,7 +76,7 @@ void InlineableFunctionLocator::visit(FunctionCall &call)
 		++count;
 		/* Don't inline functions which are called more than once or are called
 		recursively. */
-		if(count>1 || def==current_function)
+		if((count>1 && def->source!=BUILTIN_SOURCE) || def==current_function)
 			inlineable.erase(def);
 	}
 
@@ -34,8 +85,12 @@ void InlineableFunctionLocator::visit(FunctionCall &call)
 
 void InlineableFunctionLocator::visit(FunctionDeclaration &func)
 {
+	bool has_out_params = false;
+	for(NodeArray<VariableDeclaration>::const_iterator i=func.parameters.begin(); (!has_out_params && i!=func.parameters.end()); ++i)
+		has_out_params = ((*i)->interface=="out");
+
 	unsigned &count = refcounts[func.definition];
-	if(count<=1 && func.parameters.empty())
+	if((count<=1 || func.source==BUILTIN_SOURCE) && !has_out_params)
 		inlineable.insert(func.definition);
 
 	SetForScope<FunctionDeclaration *> set(current_function, &func);
@@ -66,75 +121,97 @@ void InlineableFunctionLocator::visit(Return &ret)
 
 InlineContentInjector::InlineContentInjector():
 	source_func(0),
-	remap_names(0)
+	pass(REFERENCED)
 { }
 
-const string &InlineContentInjector::apply(Stage &stage, FunctionDeclaration &target_func, Block &tgt_blk, const NodeList<Statement>::iterator &ins_pt, FunctionDeclaration &src)
+string InlineContentInjector::apply(Stage &stage, FunctionDeclaration &target_func, Block &tgt_blk, const NodeList<Statement>::iterator &ins_pt, FunctionCall &call)
 {
+	source_func = call.declaration->definition;
+
+	/* Populate referenced_names from the target function so we can rename
+	variables from the inlined function that would conflict. */
+	pass = REFERENCED;
+	target_func.visit(*this);
+
+	/* Inline and rename passes must be interleaved so used variable names are
+	known when inlining the return statement. */
+	pass = INLINE;
 	staging_block.parent = &tgt_blk;
-	source_func = &src;
-	remap_prefix = source_func->name;
+	staging_block.variables.clear();
+
+	vector<RefPtr<VariableDeclaration> > params;
+	params.reserve(source_func->parameters.size());
+	for(NodeArray<VariableDeclaration>::iterator i=source_func->parameters.begin(); i!=source_func->parameters.end(); ++i)
+	{
+		RefPtr<VariableDeclaration> var = (*i)->clone();
+		var->interface.clear();
+
+		SetForScope<Pass> set_pass(pass, RENAME);
+		var->visit(*this);
+
+		staging_block.body.push_back_nocopy(var);
+		params.push_back(var);
+	}
 
-	for(NodeList<Statement>::iterator i=src.body.body.begin(); i!=src.body.body.end(); ++i)
+	for(NodeList<Statement>::iterator i=source_func->body.body.begin(); i!=source_func->body.body.end(); ++i)
 	{
 		r_inlined_statement = 0;
 		(*i)->visit(*this);
 		if(!r_inlined_statement)
 			r_inlined_statement = (*i)->clone();
 
-		SetForScope<unsigned> set_remap(remap_names, 2);
+		SetForScope<Pass> set_pass(pass, RENAME);
 		r_inlined_statement->visit(*this);
-		staging_block.body.push_back(r_inlined_statement);
+
+		staging_block.body.push_back_nocopy(r_inlined_statement);
 	}
 
-	SetForScope<unsigned> set_remap(remap_names, 1);
-	SetForScope<string> set_prefix(remap_prefix, target_func.name);
+	/* Now collect names from the staging block.  Local variables that would
+	have conflicted with the target function were renamed earlier. */
+	pass = REFERENCED;
+	referenced_names.clear();
 	staging_block.variables.clear();
+	staging_block.visit(*this);
+
+	/* Rename variables in the target function so they don't interfere with
+	global identifiers used by the source function. */
+	pass = RENAME;
+	staging_block.parent = source_func->body.parent;
 	target_func.visit(*this);
 
+	// Put the argument expressions in place after all renaming has been done.
+	for(unsigned i=0; i<source_func->parameters.size(); ++i)
+		params[i]->init_expression = call.arguments[i]->clone();
+
 	tgt_blk.body.splice(ins_pt, staging_block.body);
 
-	NodeReorderer().apply(stage, target_func, dependencies);
+	NodeReorderer().apply(stage, target_func, DependencyCollector().apply(*source_func));
 
 	return r_result_name;
 }
 
 void InlineContentInjector::visit(VariableReference &var)
 {
-	if(remap_names)
+	if(pass==RENAME)
 	{
 		map<string, VariableDeclaration *>::const_iterator i = staging_block.variables.find(var.name);
 		if(i!=staging_block.variables.end())
 			var.name = i->second->name;
 	}
-	else if(var.declaration)
-	{
-		if(!staging_block.variables.count(var.name))
-		{
-			dependencies.insert(var.declaration);
-			referenced_names.insert(var.name);
-		}
-		var.declaration->visit(*this);
-	}
+	else if(pass==REFERENCED)
+		referenced_names.insert(var.name);
 }
 
 void InlineContentInjector::visit(InterfaceBlockReference &iface)
 {
-	if(!remap_names && iface.declaration)
-	{
-		dependencies.insert(iface.declaration);
+	if(pass==REFERENCED)
 		referenced_names.insert(iface.name);
-		iface.declaration->visit(*this);
-	}
 }
 
 void InlineContentInjector::visit(FunctionCall &call)
 {
-	if(!remap_names && call.declaration)
-	{
-		dependencies.insert(call.declaration);
+	if(pass==REFERENCED)
 		referenced_names.insert(call.name);
-	}
 	TraversingVisitor::visit(call);
 }
 
@@ -142,34 +219,34 @@ void InlineContentInjector::visit(VariableDeclaration &var)
 {
 	TraversingVisitor::visit(var);
 
-	if(remap_names)
+	if(pass==RENAME)
 	{
-		if(remap_names==2 || referenced_names.count(var.name))
+		/* Check against conflicts with the other context as well as variables
+		already renamed here. */
+		bool conflict = (staging_block.variables.count(var.name) || referenced_names.count(var.name));
+		staging_block.variables[var.name] = &var;
+		if(conflict)
 		{
-			string mapped_name = get_unused_variable_name(staging_block, var.name, remap_prefix);
-			staging_block.variables[var.name] = &var;
+			string mapped_name = get_unused_variable_name(staging_block, var.name);
 			if(mapped_name!=var.name)
+			{
 				staging_block.variables[mapped_name] = &var;
-			var.name = mapped_name;
+				var.name = mapped_name;
+			}
 		}
 	}
-	else if(var.type_declaration)
-	{
-		dependencies.insert(var.type_declaration);
-		referenced_names.insert(var.type_declaration->name);
-		var.type_declaration->visit(*this);
-	}
+	else if(pass==REFERENCED)
+		referenced_names.insert(var.type);
 }
 
 void InlineContentInjector::visit(Return &ret)
 {
 	TraversingVisitor::visit(ret);
 
-	if(!remap_names && ret.expression)
+	if(pass==INLINE && ret.expression)
 	{
-		/* Create a new variable to hold the return value of the inlined
-		function. */
-		r_result_name = get_unused_variable_name(staging_block, "_return", source_func->name);
+		// Create a new variable to hold the return value of the inlined function.
+		r_result_name = get_unused_variable_name(staging_block, "_return");
 		RefPtr<VariableDeclaration> var = new VariableDeclaration;
 		var->source = ret.source;
 		var->line = ret.line;
@@ -221,23 +298,23 @@ void FunctionInliner::visit(Block &block)
 
 void FunctionInliner::visit(FunctionCall &call)
 {
+	for(NodeArray<Expression>::iterator i=call.arguments.begin(); (!r_inlined_here && i!=call.arguments.end()); ++i)
+		visit(*i);
+
 	if(r_inlined_here)
 		return;
 
-	for(NodeArray<Expression>::iterator i=call.arguments.begin(); i!=call.arguments.end(); ++i)
-		visit(*i);
-
 	FunctionDeclaration *def = call.declaration;
 	if(def)
 		def = def->definition;
 
 	if(def && inlineable.count(def))
 	{
-		string result_name = InlineContentInjector().apply(*stage, *current_function, *current_block, insert_point, *def);
+		string result_name = InlineContentInjector().apply(*stage, *current_function, *current_block, insert_point, call);
 
 		// This will later get removed by UnusedVariableRemover.
 		if(result_name.empty())
-			result_name = "msp_unused_from_inline";
+			result_name = "_msp_unused_from_inline";
 
 		RefPtr<VariableReference> ref = new VariableReference;
 		ref->name = result_name;
@@ -272,15 +349,6 @@ void FunctionInliner::visit(Iteration &iter)
 }
 
 
-ExpressionInliner::ExpressionInfo::ExpressionInfo():
-	expression(0),
-	assign_scope(0),
-	inline_point(0),
-	trivial(false),
-	available(true)
-{ }
-
-
 ExpressionInliner::ExpressionInliner():
 	r_ref_info(0),
 	r_any_inlined(false),
@@ -486,18 +554,6 @@ void ExpressionInliner::visit(Iteration &iter)
 }
 
 
-BasicTypeDeclaration::Kind ConstantFolder::get_value_kind(const Variant &value)
-{
-	if(value.check_type<bool>())
-		return BasicTypeDeclaration::BOOL;
-	else if(value.check_type<int>())
-		return BasicTypeDeclaration::INT;
-	else if(value.check_type<float>())
-		return BasicTypeDeclaration::FLOAT;
-	else
-		return BasicTypeDeclaration::VOID;
-}
-
 template<typename T>
 T ConstantFolder::evaluate_logical(char oper, T left, T right)
 {
@@ -536,6 +592,31 @@ T ConstantFolder::evaluate_arithmetic(char oper, T left, T right)
 	}
 }
 
+template<typename T>
+T ConstantFolder::evaluate_int_special_op(char oper, T left, T right)
+{
+	switch(oper)
+	{
+	case '%': return left%right;
+	case '<': return left<<right;
+	case '>': return left>>right;
+	default: return T();
+	}
+}
+
+template<typename T>
+void ConstantFolder::convert_to_result(const Variant &value)
+{
+	if(value.check_type<bool>())
+		set_result(static_cast<T>(value.value<bool>()));
+	else if(value.check_type<int>())
+		set_result(static_cast<T>(value.value<int>()));
+	else if(value.check_type<unsigned>())
+		set_result(static_cast<T>(value.value<unsigned>()));
+	else if(value.check_type<float>())
+		set_result(static_cast<T>(value.value<float>()));
+}
+
 void ConstantFolder::set_result(const Variant &value, bool literal)
 {
 	r_constant_value = value;
@@ -556,22 +637,27 @@ void ConstantFolder::visit(RefPtr<Expression> &expr)
 	if(!r_constant || r_literal || r_uses_iter_var)
 		return;
 
-	BasicTypeDeclaration::Kind kind = get_value_kind(r_constant_value);
-	if(kind==BasicTypeDeclaration::VOID)
-	{
-		r_constant = false;
-		return;
-	}
-
 	RefPtr<Literal> literal = new Literal;
-	if(kind==BasicTypeDeclaration::BOOL)
+	if(r_constant_value.check_type<bool>())
 		literal->token = (r_constant_value.value<bool>() ? "true" : "false");
-	else if(kind==BasicTypeDeclaration::INT)
+	else if(r_constant_value.check_type<int>())
 		literal->token = lexical_cast<string>(r_constant_value.value<int>());
-	else if(kind==BasicTypeDeclaration::FLOAT)
+	else if(r_constant_value.check_type<unsigned>())
+		literal->token = lexical_cast<string>(r_constant_value.value<unsigned>())+"u";
+	else if(r_constant_value.check_type<float>())
+	{
 		literal->token = lexical_cast<string>(r_constant_value.value<float>());
+		if(isnumrc(literal->token))
+			literal->token += ".0";
+	}
+	else
+	{
+		r_constant = false;
+		return;
+	}
 	literal->value = r_constant_value;
 	expr = literal;
+	r_any_folded = true;
 }
 
 void ConstantFolder::visit(Literal &literal)
@@ -611,25 +697,27 @@ void ConstantFolder::visit(UnaryExpression &unary)
 	if(!can_fold)
 		return;
 
-	BasicTypeDeclaration::Kind kind = get_value_kind(r_constant_value);
-
 	char oper = unary.oper->token[0];
 	char oper2 = unary.oper->token[1];
 	if(oper=='!')
 	{
-		if(kind==BasicTypeDeclaration::BOOL)
+		if(r_constant_value.check_type<bool>())
 			set_result(!r_constant_value.value<bool>());
 	}
 	else if(oper=='~')
 	{
-		if(kind==BasicTypeDeclaration::INT)
+		if(r_constant_value.check_type<int>())
 			set_result(~r_constant_value.value<int>());
+		else if(r_constant_value.check_type<unsigned>())
+			set_result(~r_constant_value.value<unsigned>());
 	}
 	else if(oper=='-' && !oper2)
 	{
-		if(kind==BasicTypeDeclaration::INT)
+		if(r_constant_value.check_type<int>())
 			set_result(-r_constant_value.value<int>());
-		else if(kind==BasicTypeDeclaration::FLOAT)
+		else if(r_constant_value.check_type<unsigned>())
+			set_result(-r_constant_value.value<unsigned>());
+		else if(r_constant_value.check_type<float>())
 			set_result(-r_constant_value.value<float>());
 	}
 }
@@ -649,53 +737,54 @@ void ConstantFolder::visit(BinaryExpression &binary)
 	if(!can_fold)
 		return;
 
-	BasicTypeDeclaration::Kind left_kind = get_value_kind(left_value);
-	BasicTypeDeclaration::Kind right_kind = get_value_kind(r_constant_value);
 	// Currently only expressions with both sides of equal types are handled.
-	if(left_kind!=right_kind)
+	if(!left_value.check_same_type(r_constant_value))
 		return;
 
 	char oper = binary.oper->token[0];
 	char oper2 = binary.oper->token[1];
 	if(oper=='&' || oper=='|' || oper=='^')
 	{
-		if(oper2==oper && left_kind==BasicTypeDeclaration::BOOL)
+		if(oper2==oper && left_value.check_type<bool>())
 			set_result(evaluate_logical(oper, left_value.value<bool>(), r_constant_value.value<bool>()));
-		else if(!oper2 && left_kind==BasicTypeDeclaration::INT)
+		else if(!oper2 && left_value.check_type<int>())
 			set_result(evaluate_logical(oper, left_value.value<int>(), r_constant_value.value<int>()));
+		else if(!oper2 && left_value.check_type<unsigned>())
+			set_result(evaluate_logical(oper, left_value.value<unsigned>(), r_constant_value.value<unsigned>()));
 	}
 	else if((oper=='<' || oper=='>') && oper2!=oper)
 	{
-		if(left_kind==BasicTypeDeclaration::INT)
+		if(left_value.check_type<int>())
 			set_result(evaluate_relation(binary.oper->token, left_value.value<int>(), r_constant_value.value<int>()));
-		else if(left_kind==BasicTypeDeclaration::FLOAT)
+		else if(left_value.check_type<unsigned>())
+			set_result(evaluate_relation(binary.oper->token, left_value.value<unsigned>(), r_constant_value.value<unsigned>()));
+		else if(left_value.check_type<float>())
 			set_result(evaluate_relation(binary.oper->token, left_value.value<float>(), r_constant_value.value<float>()));
 	}
 	else if((oper=='=' || oper=='!') && oper2=='=')
 	{
-		if(left_kind==BasicTypeDeclaration::INT)
+		if(left_value.check_type<int>())
 			set_result((left_value.value<int>()==r_constant_value.value<int>()) == (oper=='='));
-		if(left_kind==BasicTypeDeclaration::FLOAT)
+		else if(left_value.check_type<unsigned>())
+			set_result((left_value.value<unsigned>()==r_constant_value.value<unsigned>()) == (oper=='='));
+		else if(left_value.check_type<float>())
 			set_result((left_value.value<float>()==r_constant_value.value<float>()) == (oper=='='));
 	}
 	else if(oper=='+' || oper=='-' || oper=='*' || oper=='/')
 	{
-		if(left_kind==BasicTypeDeclaration::INT)
+		if(left_value.check_type<int>())
 			set_result(evaluate_arithmetic(oper, left_value.value<int>(), r_constant_value.value<int>()));
-		else if(left_kind==BasicTypeDeclaration::FLOAT)
+		else if(left_value.check_type<unsigned>())
+			set_result(evaluate_arithmetic(oper, left_value.value<unsigned>(), r_constant_value.value<unsigned>()));
+		else if(left_value.check_type<float>())
 			set_result(evaluate_arithmetic(oper, left_value.value<float>(), r_constant_value.value<float>()));
 	}
 	else if(oper=='%' || ((oper=='<' || oper=='>') && oper2==oper))
 	{
-		if(left_kind!=BasicTypeDeclaration::INT)
-			return;
-
-		if(oper=='%')
-			set_result(left_value.value<int>()%r_constant_value.value<int>());
-		else if(oper=='<')
-			set_result(left_value.value<int>()<<r_constant_value.value<int>());
-		else if(oper=='>')
-			set_result(left_value.value<int>()>>r_constant_value.value<int>());
+		if(left_value.check_type<int>())
+			set_result(evaluate_int_special_op(oper, left_value.value<int>(), r_constant_value.value<int>()));
+		else if(left_value.check_type<unsigned>())
+			set_result(evaluate_int_special_op(oper, left_value.value<unsigned>(), r_constant_value.value<unsigned>()));
 	}
 }
 
@@ -713,6 +802,30 @@ void ConstantFolder::visit(TernaryExpression &ternary)
 
 void ConstantFolder::visit(FunctionCall &call)
 {
+	if(call.constructor && call.type && call.arguments.size()==1)
+	{
+		const BasicTypeDeclaration *basic = dynamic_cast<const BasicTypeDeclaration *>(call.type);
+		if(basic)
+		{
+			call.arguments[0]->visit(*this);
+			bool can_fold = r_constant;
+			r_constant = false;
+			if(!can_fold)
+				return;
+
+			if(basic->kind==BasicTypeDeclaration::BOOL)
+				convert_to_result<bool>(r_constant_value);
+			else if(basic->kind==BasicTypeDeclaration::INT && basic->size==32 && basic->sign)
+				convert_to_result<int>(r_constant_value);
+			else if(basic->kind==BasicTypeDeclaration::INT && basic->size==32 && !basic->sign)
+				convert_to_result<unsigned>(r_constant_value);
+			else if(basic->kind==BasicTypeDeclaration::FLOAT && basic->size==32)
+				convert_to_result<float>(r_constant_value);
+
+			return;
+		}
+	}
+
 	TraversingVisitor::visit(call);
 	r_constant = false;
 }
@@ -840,40 +953,63 @@ void ConstantConditionEliminator::visit(Iteration &iter)
 }
 
 
-bool UnusedTypeRemover::apply(Stage &stage)
+UnreachableCodeRemover::UnreachableCodeRemover():
+	reachable(true)
+{ }
+
+bool UnreachableCodeRemover::apply(Stage &stage)
 {
 	stage.content.visit(*this);
-	NodeRemover().apply(stage, unused_nodes);
-	return !unused_nodes.empty();
+	NodeRemover().apply(stage, unreachable_nodes);
+	return !unreachable_nodes.empty();
 }
 
-void UnusedTypeRemover::visit(Literal &literal)
+void UnreachableCodeRemover::visit(Block &block)
 {
-	unused_nodes.erase(literal.type);
+	NodeList<Statement>::iterator i = block.body.begin();
+	for(; (reachable && i!=block.body.end()); ++i)
+		(*i)->visit(*this);
+	for(; i!=block.body.end(); ++i)
+		unreachable_nodes.insert(i->get());
 }
 
-void UnusedTypeRemover::visit(UnaryExpression &unary)
+void UnreachableCodeRemover::visit(FunctionDeclaration &func)
 {
-	unused_nodes.erase(unary.type);
-	TraversingVisitor::visit(unary);
+	TraversingVisitor::visit(func);
+	reachable = true;
 }
 
-void UnusedTypeRemover::visit(BinaryExpression &binary)
+void UnreachableCodeRemover::visit(Conditional &cond)
 {
-	unused_nodes.erase(binary.type);
-	TraversingVisitor::visit(binary);
+	cond.body.visit(*this);
+	bool reachable_if_true = reachable;
+	reachable = true;
+	cond.else_body.visit(*this);
+
+	reachable |= reachable_if_true;
 }
 
-void UnusedTypeRemover::visit(TernaryExpression &ternary)
+void UnreachableCodeRemover::visit(Iteration &iter)
 {
-	unused_nodes.erase(ternary.type);
-	TraversingVisitor::visit(ternary);
+	TraversingVisitor::visit(iter);
+
+	/* Always consider code after a loop reachable, since there's no checking
+	for whether the loop executes. */
+	reachable = true;
 }
 
-void UnusedTypeRemover::visit(FunctionCall &call)
+
+bool UnusedTypeRemover::apply(Stage &stage)
 {
-	unused_nodes.erase(call.type);
-	TraversingVisitor::visit(call);
+	stage.content.visit(*this);
+	NodeRemover().apply(stage, unused_nodes);
+	return !unused_nodes.empty();
+}
+
+void UnusedTypeRemover::visit(RefPtr<Expression> &expr)
+{
+	unused_nodes.erase(expr->type);
+	TraversingVisitor::visit(expr);
 }
 
 void UnusedTypeRemover::visit(BasicTypeDeclaration &type)
@@ -899,6 +1035,7 @@ void UnusedTypeRemover::visit(StructDeclaration &strct)
 void UnusedTypeRemover::visit(VariableDeclaration &var)
 {
 	unused_nodes.erase(var.type_declaration);
+	TraversingVisitor::visit(var);
 }
 
 void UnusedTypeRemover::visit(InterfaceBlock &iface)
@@ -918,7 +1055,10 @@ UnusedVariableRemover::UnusedVariableRemover():
 	interface_block(0),
 	r_assignment(0),
 	assignment_target(false),
-	r_side_effects(false)
+	r_side_effects(false),
+	in_struct(false),
+	composite_reference(false),
+	in_loop(0)
 { }
 
 bool UnusedVariableRemover::apply(Stage &s)
@@ -930,10 +1070,6 @@ bool UnusedVariableRemover::apply(Stage &s)
 		if(i->used_by.empty())
 			unused_nodes.insert(i->node);
 
-	for(map<string, InterfaceBlock *>::const_iterator i=s.interface_blocks.begin(); i!=s.interface_blocks.end(); ++i)
-		if(i->second->instance_name.empty())
-			unused_nodes.insert(i->second);
-
 	for(BlockVariableMap::const_iterator i=variables.begin(); i!=variables.end(); ++i)
 	{
 		if(i->second.output)
@@ -966,19 +1102,90 @@ void UnusedVariableRemover::referenced(const Assignment::Target &target, Node &n
 	var_info.referenced = true;
 	if(!assignment_target)
 	{
+		bool loop_external = false;
 		for(vector<AssignmentInfo *>::const_iterator i=var_info.assignments.begin(); i!=var_info.assignments.end(); ++i)
-			(*i)->used_by.push_back(&node);
+		{
+			bool covered = true;
+			for(unsigned j=0; (covered && j<(*i)->target.chain_len && j<target.chain_len); ++j)
+			{
+				Assignment::Target::ChainType type1 = static_cast<Assignment::Target::ChainType>((*i)->target.chain[j]&0xC0);
+				Assignment::Target::ChainType type2 = static_cast<Assignment::Target::ChainType>(target.chain[j]&0xC0);
+				if(type1==Assignment::Target::SWIZZLE || type2==Assignment::Target::SWIZZLE)
+				{
+					unsigned index1 = (*i)->target.chain[j]&0x3F;
+					unsigned index2 = target.chain[j]&0x3F;
+					if(type1==Assignment::Target::SWIZZLE && type2==Assignment::Target::SWIZZLE)
+						covered = index1&index2;
+					else if(type1==Assignment::Target::ARRAY && index1<4)
+						covered = index2&(1<<index1);
+					else if(type2==Assignment::Target::ARRAY && index2<4)
+						covered = index1&(1<<index2);
+					/* If it's some other combination (shouldn't happen), leave
+					covered as true */
+				}
+				else
+					covered = ((*i)->target.chain[j]==target.chain[j]);
+			}
+
+			if(covered)
+			{
+				(*i)->used_by.push_back(&node);
+				if((*i)->in_loop<in_loop)
+					loop_external = true;
+			}
+		}
+
+		if(loop_external)
+			loop_ext_refs.push_back(&node);
 	}
 }
 
 void UnusedVariableRemover::visit(VariableReference &var)
 {
-	referenced(var.declaration, var);
+	if(composite_reference)
+		r_reference.declaration = var.declaration;
+	else
+		referenced(var.declaration, var);
 }
 
 void UnusedVariableRemover::visit(InterfaceBlockReference &iface)
 {
-	referenced(iface.declaration, iface);
+	if(composite_reference)
+		r_reference.declaration = iface.declaration;
+	else
+		referenced(iface.declaration, iface);
+}
+
+void UnusedVariableRemover::visit_composite(Expression &expr)
+{
+	if(!composite_reference)
+		r_reference = Assignment::Target();
+
+	SetFlag set_composite(composite_reference);
+	expr.visit(*this);
+}
+
+void UnusedVariableRemover::visit(MemberAccess &memacc)
+{
+	visit_composite(*memacc.left);
+
+	add_to_chain(r_reference, Assignment::Target::MEMBER, memacc.index);
+
+	if(!composite_reference && r_reference.declaration)
+		referenced(r_reference, memacc);
+}
+
+void UnusedVariableRemover::visit(Swizzle &swizzle)
+{
+	visit_composite(*swizzle.left);
+
+	unsigned mask = 0;
+	for(unsigned i=0; i<swizzle.count; ++i)
+		mask |= 1<<swizzle.components[i];
+	add_to_chain(r_reference, Assignment::Target::SWIZZLE, mask);
+
+	if(!composite_reference && r_reference.declaration)
+		referenced(r_reference, swizzle);
 }
 
 void UnusedVariableRemover::visit(UnaryExpression &unary)
@@ -992,12 +1199,30 @@ void UnusedVariableRemover::visit(BinaryExpression &binary)
 {
 	if(binary.oper->token[0]=='[')
 	{
-		binary.left->visit(*this);
-		SetFlag set(assignment_target, false);
-		binary.right->visit(*this);
+		visit_composite(*binary.left);
+
+		{
+			SetFlag clear_assignment(assignment_target, false);
+			SetFlag clear_composite(composite_reference, false);
+			binary.right->visit(*this);
+		}
+
+		add_to_chain(r_reference, Assignment::Target::ARRAY, 0x3F);
+
+		if(!composite_reference && r_reference.declaration)
+			referenced(r_reference, binary);
 	}
 	else
+	{
+		SetFlag clear_composite(composite_reference, false);
 		TraversingVisitor::visit(binary);
+	}
+}
+
+void UnusedVariableRemover::visit(TernaryExpression &ternary)
+{
+	SetFlag clear_composite(composite_reference, false);
+	TraversingVisitor::visit(ternary);
 }
 
 void UnusedVariableRemover::visit(Assignment &assign)
@@ -1013,6 +1238,7 @@ void UnusedVariableRemover::visit(Assignment &assign)
 
 void UnusedVariableRemover::visit(FunctionCall &call)
 {
+	SetFlag clear_composite(composite_reference, false);
 	TraversingVisitor::visit(call);
 	/* Treat function calls as having side effects so expression statements
 	consisting of nothing but a function call won't be optimized away. */
@@ -1032,6 +1258,7 @@ void UnusedVariableRemover::record_assignment(const Assignment::Target &target,
 	AssignmentInfo &assign_info = assignments.back();
 	assign_info.node = &node;
 	assign_info.target = target;
+	assign_info.in_loop = in_loop;
 
 	/* An assignment to the target hides any assignments to the same target or
 	its subfields. */
@@ -1064,15 +1291,26 @@ void UnusedVariableRemover::visit(ExpressionStatement &expr)
 		unused_nodes.insert(&expr);
 }
 
+void UnusedVariableRemover::visit(StructDeclaration &strct)
+{
+	SetFlag set_struct(in_struct);
+	TraversingVisitor::visit(strct);
+}
+
 void UnusedVariableRemover::visit(VariableDeclaration &var)
 {
+	TraversingVisitor::visit(var);
+
+	if(in_struct)
+		return;
+
 	VariableInfo &var_info = variables[&var];
 	var_info.interface_block = interface_block;
 
 	/* Mark variables as output if they're used by the next stage or the
 	graphics API. */
 	if(interface_block)
-		var_info.output = (interface_block->interface=="out" && (interface_block->linked_block || !interface_block->name.compare(0, 3, "gl_")));
+		var_info.output = (interface_block->interface=="out" && (interface_block->linked_block || !interface_block->block_name.compare(0, 3, "gl_")));
 	else
 		var_info.output = (var.interface=="out" && (stage->type==Stage::FRAGMENT || var.linked_declaration || !var.name.compare(0, 3, "gl_")));
 
@@ -1081,21 +1319,12 @@ void UnusedVariableRemover::visit(VariableDeclaration &var)
 		var_info.initialized = true;
 		record_assignment(&var, *var.init_expression);
 	}
-	TraversingVisitor::visit(var);
 }
 
 void UnusedVariableRemover::visit(InterfaceBlock &iface)
 {
-	if(iface.instance_name.empty())
-	{
-		SetForScope<InterfaceBlock *> set_block(interface_block, &iface);
-		iface.struct_declaration->members.visit(*this);
-	}
-	else
-	{
-		VariableInfo &var_info = variables[&iface];
-		var_info.output = (iface.interface=="out" && (iface.linked_block || !iface.name.compare(0, 3, "gl_")));
-	}
+	VariableInfo &var_info = variables[&iface];
+	var_info.output = (iface.interface=="out" && (iface.linked_block || !iface.block_name.compare(0, 3, "gl_")));
 }
 
 void UnusedVariableRemover::merge_variables(const BlockVariableMap &other_vars)
@@ -1161,7 +1390,18 @@ void UnusedVariableRemover::visit(Conditional &cond)
 void UnusedVariableRemover::visit(Iteration &iter)
 {
 	BlockVariableMap saved_vars = variables;
-	TraversingVisitor::visit(iter);
+	vector<Node *> saved_refs;
+	swap(loop_ext_refs, saved_refs);
+	{
+		SetForScope<unsigned> set_loop(in_loop, in_loop+1);
+		TraversingVisitor::visit(iter);
+	}
+	swap(loop_ext_refs, saved_refs);
+
+	/* Visit the external references of the loop again to record assignments
+	done in the loop as used. */
+	for(vector<Node *>::const_iterator i=saved_refs.begin(); i!=saved_refs.end(); ++i)
+		(*i)->visit(*this);
 
 	/* Merge assignments from the iteration, without clearing previous state.
 	Further analysis is needed to determine which parts of the iteration body