diff --git a/test/hotspot/jtreg/compiler/lib/template_framework/library/Operations.java b/test/hotspot/jtreg/compiler/lib/template_framework/library/Operations.java
index 1fe05cc2b6c..dd778050050 100644
--- a/test/hotspot/jtreg/compiler/lib/template_framework/library/Operations.java
+++ b/test/hotspot/jtreg/compiler/lib/template_framework/library/Operations.java
@@ -129,8 +129,8 @@ public final class Operations {
             ops.add(Expression.make(type, "(", type, " + ", type, ")"));
             ops.add(Expression.make(type, "(", type, " - ", type, ")"));
             ops.add(Expression.make(type, "(", type, " * ", type, ")"));
-            ops.add(Expression.make(type, "(", type, " / ", type, ")"));
-            ops.add(Expression.make(type, "(", type, " % ", type, ")"));
+            ops.add(Expression.make(type, "(", type, " / ", type, ")", WITH_ARITHMETIC_EXCEPTION));
+            ops.add(Expression.make(type, "(", type, " % ", type, ")", WITH_ARITHMETIC_EXCEPTION));
 
             // Relational / Comparison Operators
             ops.add(Expression.make(BOOLEANS, "(", type, " == ", type, ")"));
diff --git a/test/hotspot/jtreg/compiler/lib/template_framework/library/PrimitiveType.java b/test/hotspot/jtreg/compiler/lib/template_framework/library/PrimitiveType.java
index b789da45d44..ceed5546812 100644
--- a/test/hotspot/jtreg/compiler/lib/template_framework/library/PrimitiveType.java
+++ b/test/hotspot/jtreg/compiler/lib/template_framework/library/PrimitiveType.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2025, 2026, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -71,7 +71,22 @@ public final class PrimitiveType implements CodeGenerationDataNameType {
 
     @Override
     public boolean isSubtypeOf(DataName.Type other) {
-        return (other instanceof PrimitiveType pt) && pt.kind == kind;
+        // Implement other >: this according to JLS §4.10.1.
+        if (other instanceof PrimitiveType pt) {
+            if (pt.kind == Kind.BOOLEAN || kind == Kind.BOOLEAN) {
+                // Boolean does not have a supertype and only itself as a subtype.
+                return pt.kind == kind;
+            }
+            if (pt.kind == Kind.CHAR || kind == Kind.CHAR) {
+                // Char does not have a subtype, but .
+                // The following is correct for the subtype relation to floats, since chars are 16 bits wide and floats 32 bits or more.
+                return pt.kind == kind || (pt.byteSize() > this.byteSize() && this.kind != Kind.BYTE);
+            }
+            return (pt.isFloating() && !this.isFloating()) ||  // Due to float >: long, all integers are subtypes of floating point types.
+                   (pt.isFloating() == this.isFloating() && pt.byteSize() >= this.byteSize()); // Generally, narrower types are subtypes of wider types.
+        }
+
+        return false;
     }
 
     @Override
diff --git a/test/hotspot/jtreg/testlibrary_tests/template_framework/examples/TestPrimitiveTypes.java b/test/hotspot/jtreg/testlibrary_tests/template_framework/examples/TestPrimitiveTypes.java
index b1f5f74e682..cd1647a7768 100644
--- a/test/hotspot/jtreg/testlibrary_tests/template_framework/examples/TestPrimitiveTypes.java
+++ b/test/hotspot/jtreg/testlibrary_tests/template_framework/examples/TestPrimitiveTypes.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2025, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2025, 2026, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -48,6 +48,7 @@ import static compiler.lib.template_framework.Template.let;
 import static compiler.lib.template_framework.Template.$;
 import static compiler.lib.template_framework.Template.addDataName;
 import static compiler.lib.template_framework.DataName.Mutability.MUTABLE;
+import static compiler.lib.template_framework.DataName.Mutability.MUTABLE_OR_IMMUTABLE;
 
 import compiler.lib.template_framework.library.Hooks;
 import compiler.lib.template_framework.library.CodeGenerationDataNameType;
@@ -129,7 +130,8 @@ public class TestPrimitiveTypes {
         }
 
         // Finally, test the type by creating some DataNames (variables), and sampling
-        // from them. There should be no cross-over between the types.
+        // from them. Sampling exactly should not lead to any conversion and sampling
+        // subtypes should only lead to widening conversions.
         // IMPORTANT: since we are adding the DataName via an inserted Template, we
         //            must chose a "transparentScope", so that the DataName escapes. If we
         //            instead chose "scope", the test would fail, because it later
@@ -150,6 +152,14 @@ public class TestPrimitiveTypes {
             """
         ));
 
+        var assignmentTemplate = Template.make("lhsType", (PrimitiveType lhsType) -> scope(
+            dataNames(MUTABLE).exactOf(lhsType).sampleAndLetAs("lhs"),
+            dataNames(MUTABLE_OR_IMMUTABLE).subtypeOf(lhsType).sampleAndLetAs("rhs"),
+            """
+            #lhs = #rhs;
+            """
+        ));
+
         var namesTemplate = Template.make(() -> scope(
             """
             public static void test_names() {
@@ -161,10 +171,16 @@ public class TestPrimitiveTypes {
                     ).toList()
                 ),
                 """
-                // Now sample:
+                // Sample exactly:
                 """,
                 Collections.nCopies(10,
                     CodeGenerationDataNameType.PRIMITIVE_TYPES.stream().map(sampleTemplate::asToken).toList()
+                ),
+                """
+                // Sample subtypes:
+                """,
+                Collections.nCopies(10,
+                    CodeGenerationDataNameType.PRIMITIVE_TYPES.stream().map(assignmentTemplate::asToken).toList()
                 )
             )),
             """