From: Mikko Rasa <tdb@tdb.fi>
Date: Sat, 9 Oct 2021 16:46:27 +0000 (+0300)
Subject: Recognize unknown index as matching any index
X-Git-Url: http://git.tdb.fi/?p=libs%2Fgl.git;a=commitdiff_plain;h=e2ed3de4cbbc682ff490a3b0b760b8a45260f611

Recognize unknown index as matching any index

If an array is accessed with an unknown index, all assignments to the
array must be kept.
---

diff --git a/source/glsl/optimize.cpp b/source/glsl/optimize.cpp
index 350e2eb7..768cfd5d 100644
--- a/source/glsl/optimize.cpp
+++ b/source/glsl/optimize.cpp
@@ -1242,10 +1242,10 @@ void UnusedVariableRemover::referenced(const Assignment::Target &target, Node &n
 			{
 				Assignment::Target::ChainType type1 = static_cast<Assignment::Target::ChainType>(a->target.chain[j]&0xC0);
 				Assignment::Target::ChainType type2 = static_cast<Assignment::Target::ChainType>(target.chain[j]&0xC0);
+				unsigned index1 = a->target.chain[j]&0x3F;
+				unsigned index2 = target.chain[j]&0x3F;
 				if(type1==Assignment::Target::SWIZZLE || type2==Assignment::Target::SWIZZLE)
 				{
-					unsigned index1 = a->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)
@@ -1256,7 +1256,7 @@ void UnusedVariableRemover::referenced(const Assignment::Target &target, Node &n
 					covered as true */
 				}
 				else
-					covered = (a->target.chain[j]==target.chain[j]);
+					covered = (type1==type2 && (index1==index2 || index1==0x3F || index2==0x3F));
 			}
 
 			if(covered)
diff --git a/tests/glsl/array_element_assignment.glsl b/tests/glsl/array_element_assignment.glsl
new file mode 100644
index 00000000..eb98ddc4
--- /dev/null
+++ b/tests/glsl/array_element_assignment.glsl
@@ -0,0 +1,26 @@
+#pragma MSP stage(vertex)
+void main()
+{
+	float a[3];
+	a[0] = 0.0;
+	a[1] = 1.0;
+	a[2] = 2.0;
+	float s = 0.0;
+	for(int i=0; i<3; ++i)
+		s += a[i];
+	gl_Position = vec4(s);
+}
+
+/* Expected output: vertex
+void main()
+{
+	float a[3];
+	a[0] = 0.0;
+	a[1] = 1.0;
+	a[2] = 2.0;
+	float s = 0.0;
+	for(int i = 0; i<3; ++i)
+		s += a[i];
+	gl_Position = vec4(s);
+}
+*/