JVM IR: Optimize type checks to null checks if possible

compiler/ir/backend.jvm/src/org/jetbrains/kotlin/backend/jvm/lower/TypeOperatorLowering.kt

@@ -69,6 +69,8 @@ private class TypeOperatorLowering(private val context: JvmBackendContext) : Fil
                     )
                 }
             }
+            argument.type.isNullable() && !type.isNullable() && argument.type.erasedUpperBound == type.erasedUpperBound ->
+                irNotEquals(argument, irNull())
             else -> irIs(argument, type.makeNotNull())
         }
     }

compiler/testData/codegen/bytecodeText/builtinFunctions/genericParameterBridge/notNullAnyMC.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
 abstract class A8 : MutableCollection<Any> {
     override fun contains(o: Any): Boolean {
         throw UnsupportedOperationException()
@@ -8,5 +7,9 @@ abstract class A8 : MutableCollection<Any> {
 // 1 bridge
 // 1 public final bridge size
 // 0 INSTANCEOF
-/* Only 1 IFNULL should be within contains method */
+
+/* Only 1 null check should be within the contains method */
+// JVM_TEMPLATES:
 // 1 IFNULL
+// JVM_IR_TEMPLATES:
+// 1 IFNONNULL

compiler/testData/codegen/bytecodeText/builtinFunctions/genericParameterBridge/notNullParamMC.kt

@@ -1,4 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
 abstract class A<T : Any> : MutableCollection<T> {
     override fun contains(o: T): Boolean {
         throw UnsupportedOperationException()
@@ -8,5 +7,9 @@ abstract class A<T : Any> : MutableCollection<T> {
 // 1 bridge
 // 1 public final bridge size
 // 0 INSTANCEOF
-/* Only 1 IFNULL should be within contains method (because T is not nullable) */
+
+/* Only 1 null check should be within the contains method (because T is not nullable) */
+// JVM_TEMPLATES:
 // 1 IFNULL
+// JVM_IR_TEMPLATES:
+// 1 IFNONNULL