KT-36813 Generate optimizable null checks in JVM_IR

compiler/fir/fir2ir/tests/org/jetbrains/kotlin/codegen/ir/FirBlackBoxCodegenTestGenerated.java

@@ -16403,6 +16403,11 @@ public class FirBlackBoxCodegenTestGenerated extends AbstractFirBlackBoxCodegenT
         public void testTrivialInstanceOf() throws Exception {
             runTest("compiler/testData/codegen/box/nullCheckOptimization/trivialInstanceOf.kt");
         }
+
+        @TestMetadata("varModifiedAfterCheck.kt")
+        public void testVarModifiedAfterCheck() throws Exception {
+            runTest("compiler/testData/codegen/box/nullCheckOptimization/varModifiedAfterCheck.kt");
+        }
     }
 
     @TestMetadata("compiler/testData/codegen/box/objectIntrinsics")

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

@@ -20,13 +20,11 @@ import org.jetbrains.kotlin.ir.UNDEFINED_OFFSET
 import org.jetbrains.kotlin.ir.builders.*
 import org.jetbrains.kotlin.ir.declarations.IrDeclaration
 import org.jetbrains.kotlin.ir.declarations.IrFile
-import org.jetbrains.kotlin.ir.expressions.IrExpression
+import org.jetbrains.kotlin.ir.expressions.*
-import org.jetbrains.kotlin.ir.expressions.IrStatementOrigin
-import org.jetbrains.kotlin.ir.expressions.IrTypeOperator
-import org.jetbrains.kotlin.ir.expressions.IrTypeOperatorCall
 import org.jetbrains.kotlin.ir.expressions.impl.IrCompositeImpl
 import org.jetbrains.kotlin.ir.symbols.IrFunctionSymbol
 import org.jetbrains.kotlin.ir.symbols.IrTypeParameterSymbol
+import org.jetbrains.kotlin.ir.symbols.IrValueSymbol
 import org.jetbrains.kotlin.ir.types.*
 import org.jetbrains.kotlin.ir.util.render
 import org.jetbrains.kotlin.ir.visitors.IrElementVisitorVoid
@@ -142,7 +140,7 @@ private class TypeOperatorLowering(private val context: JvmBackendContext) : Fil
                 val (startOffset, endOffset) = expression.extents()
                 val source = sourceViewFor(parent as IrDeclaration).subSequence(startOffset, endOffset).toString()
 
-                irLetS(expression.argument.transformVoid()) { valueSymbol ->
+                fun checkExpressionValue(valueSymbol: IrValueSymbol): IrExpression =
                     irComposite(resultType = expression.type) {
                         +irCall(checkExpressionValueIsNotNull).apply {
                             putValueArgument(0, irGet(valueSymbol.owner))
@@ -150,6 +148,14 @@ private class TypeOperatorLowering(private val context: JvmBackendContext) : Fil
                         }
                         +irGet(valueSymbol.owner)
                     }
+
+                val argument = expression.argument.transformVoid()
+                if (argument is IrGetValue) {
+                    checkExpressionValue(argument.symbol)
+                } else {
+                    irLetS(argument) { valueSymbol ->
+                        checkExpressionValue(valueSymbol)
+                    }
                 }
             }
 

compiler/testData/codegen/box/nullCheckOptimization/varModifiedAfterCheck.kt

@@ -0,0 +1,59 @@
+// TARGET_BACKEND: JVM
+// FILE: varModifiedAfterCheck.kt
+fun implicitCheck(s: String) {}
+
+fun test1() {
+    var a = J.foo()
+    val b = a
+    a = J.bar()
+    if (b != null) {
+        if (a != null) {
+            throw AssertionError("a: $a")
+        }
+    }
+}
+
+fun test2() {
+    var a = J.foo()
+    val b = a
+    if (b != null) {
+        a = J.bar()
+        if (a != null) {
+            throw AssertionError("a: $a")
+        }
+    }
+}
+
+fun test3() {
+    var a = J.foo()
+    val b = a
+    a = J.bar()
+    implicitCheck(b)
+    if (a != null) {
+        throw AssertionError("a: $a")
+    }
+}
+
+fun test4() {
+    var a = J.foo()
+    val b = a
+    implicitCheck(b)
+    a = J.bar()
+    if (a != null) {
+        throw AssertionError("a: $a")
+    }
+}
+
+fun box(): String {
+    test1()
+    test2()
+    test3()
+    test4()
+    return "OK"
+}
+
+// FILE: J.java
+public class J {
+    public static String foo() { return ""; }
+    public static String bar() { return null; }
+}

compiler/testData/codegen/bytecodeText/nullCheckOptimization/expressionValueIsNotNull.kt

@@ -1,5 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
-// TODO KT-36813 Support code generated by JVM_IR in redundant null check optimization
 // FILE: j/J.java
 
 package j;

compiler/testData/codegen/bytecodeText/nullCheckOptimization/expressionValueIsNotNullTwice.kt

@@ -1,5 +1,3 @@
-// IGNORE_BACKEND: JVM_IR
-// TODO KT-36813 Support code generated by JVM_IR in redundant null check optimization
 // FILE: j/J.java
 
 package j;

compiler/testData/codegen/bytecodeText/nullCheckOptimization/notNullExpressionValueTwice_1_4.kt

@@ -1,6 +1,4 @@
 // !API_VERSION: LATEST
-// IGNORE_BACKEND: JVM_IR
-// TODO KT-36813 Support code generated by JVM_IR in redundant null check optimization
 // FILE: j/J.java
 
 package j;

compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java

@@ -17548,6 +17548,11 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
         public void testTrivialInstanceOf() throws Exception {
             runTest("compiler/testData/codegen/box/nullCheckOptimization/trivialInstanceOf.kt");
         }
+
+        @TestMetadata("varModifiedAfterCheck.kt")
+        public void testVarModifiedAfterCheck() throws Exception {
+            runTest("compiler/testData/codegen/box/nullCheckOptimization/varModifiedAfterCheck.kt");
+        }
     }
 
     @TestMetadata("compiler/testData/codegen/box/objectIntrinsics")

compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java

@@ -17548,6 +17548,11 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
         public void testTrivialInstanceOf() throws Exception {
             runTest("compiler/testData/codegen/box/nullCheckOptimization/trivialInstanceOf.kt");
         }
+
+        @TestMetadata("varModifiedAfterCheck.kt")
+        public void testVarModifiedAfterCheck() throws Exception {
+            runTest("compiler/testData/codegen/box/nullCheckOptimization/varModifiedAfterCheck.kt");
+        }
     }
 
     @TestMetadata("compiler/testData/codegen/box/objectIntrinsics")

compiler/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java

@@ -16403,6 +16403,11 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
         public void testTrivialInstanceOf() throws Exception {
             runTest("compiler/testData/codegen/box/nullCheckOptimization/trivialInstanceOf.kt");
         }
+
+        @TestMetadata("varModifiedAfterCheck.kt")
+        public void testVarModifiedAfterCheck() throws Exception {
+            runTest("compiler/testData/codegen/box/nullCheckOptimization/varModifiedAfterCheck.kt");
+        }
     }
 
     @TestMetadata("compiler/testData/codegen/box/objectIntrinsics")