From 4737d137d0a1c7fed868c4adc7a3d7e00ba7681c Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Tue, 20 Apr 2021 18:21:35 +0300
Subject: [PATCH] Fold type conversions of constants

---
 source/glsl/optimize.cpp                      | 33 +++++++++++++++++++
 source/glsl/optimize.h                        |  2 ++
 tests/glsl/binary_operators.glsl              |  2 +-
 tests/glsl/constructors.glsl                  |  4 +--
 .../glsl/inexact_function_argument_type.glsl  |  2 +-
 5 files changed, 39 insertions(+), 4 deletions(-)

diff --git a/source/glsl/optimize.cpp b/source/glsl/optimize.cpp
index 06ea0f49..d21512f6 100644
--- a/source/glsl/optimize.cpp
+++ b/source/glsl/optimize.cpp
@@ -604,6 +604,17 @@ T ConstantFolder::evaluate_int_special_op(char oper, T left, T right)
 	}
 }
 
+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<float>())
+		set_result(static_cast<T>(value.value<float>()));
+}
+
 void ConstantFolder::set_result(const Variant &value, bool literal)
 {
 	r_constant_value = value;
@@ -776,6 +787,28 @@ 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)
+				convert_to_result<int>(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;
 }
diff --git a/source/glsl/optimize.h b/source/glsl/optimize.h
index ed9f9134..7d064056 100644
--- a/source/glsl/optimize.h
+++ b/source/glsl/optimize.h
@@ -183,6 +183,8 @@ private:
 	static T evaluate_arithmetic(char, T, T);
 	template<typename T>
 	static T evaluate_int_special_op(char, T, T);
+	template<typename T>
+	void convert_to_result(const Variant &);
 	void set_result(const Variant &, bool = false);
 
 	virtual void visit(RefPtr<Expression> &);
diff --git a/tests/glsl/binary_operators.glsl b/tests/glsl/binary_operators.glsl
index d8496286..edf36ebb 100644
--- a/tests/glsl/binary_operators.glsl
+++ b/tests/glsl/binary_operators.glsl
@@ -52,7 +52,7 @@ void main()
 	mat2x4 m2;
 	vec4 v1 = vec4(1.0);
 	vec2 v3;
-	v3 = v1*m2+(m2*m1*float(5)*v1).xy+vec2(iv);
+	v3 = v1*m2+(m2*m1*5.0*v1).xy+vec2(iv);
 	if(b)
 		++v3;
 }
diff --git a/tests/glsl/constructors.glsl b/tests/glsl/constructors.glsl
index ddb1dcea..9b878e49 100644
--- a/tests/glsl/constructors.glsl
+++ b/tests/glsl/constructors.glsl
@@ -41,7 +41,7 @@ void main()
 {
   mat3 normal_matrix = mat3(model[0].xyz, model[1].xyz, model[2].xyz);
   tbn_light_dir = mat3(normal_matrix*tangent, normal_matrix*binormal, normal_matrix*normal)*light_dir;
-  gl_Position = view_projection*model*vec4(position, float(1));
+  gl_Position = view_projection*model*vec4(position, 1.0);
   _vs_out_texcoord = texcoord;
 }
 */
@@ -53,6 +53,6 @@ layout(location=1) in vec2 _vs_out_texcoord;
 layout(location=0) in vec3 tbn_light_dir;
 void main()
 {
-  frag_color = vec4(vec3(dot(vec3(texture(normalmap, _vs_out_texcoord).xyz)*2.0-1.0, normalize(tbn_light_dir))), float(1));
+  frag_color = vec4(vec3(dot(vec3(texture(normalmap, _vs_out_texcoord).xyz)*2.0-1.0, normalize(tbn_light_dir))), 1.0);
 }
 */
diff --git a/tests/glsl/inexact_function_argument_type.glsl b/tests/glsl/inexact_function_argument_type.glsl
index 2bbece37..627fa5d8 100644
--- a/tests/glsl/inexact_function_argument_type.glsl
+++ b/tests/glsl/inexact_function_argument_type.glsl
@@ -13,6 +13,6 @@ void main()
 layout(location=0) in vec4 position;
 void main()
 {
-	gl_Position = vec4(position.xy*float(2), 0.0, 1.0);
+	gl_Position = vec4(position.xy*2.0, 0.0, 1.0);
 }
 */
-- 
2.43.0