diff --git a/compiler/backend/src/org/jetbrains/kotlin/codegen/ieee754.kt b/compiler/backend/src/org/jetbrains/kotlin/codegen/ieee754.kt
index 5ada2ef3cb4..cdd1b9f8165 100644
--- a/compiler/backend/src/org/jetbrains/kotlin/codegen/ieee754.kt
+++ b/compiler/backend/src/org/jetbrains/kotlin/codegen/ieee754.kt
@@ -10,9 +10,9 @@ import org.jetbrains.kotlin.codegen.state.KotlinTypeMapper
 import org.jetbrains.kotlin.config.LanguageVersionSettings
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
 import org.jetbrains.kotlin.psi.KtExpression
+import org.jetbrains.kotlin.psi.KtProperty
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.bindingContextUtil.getDataFlowInfoBefore
-import org.jetbrains.kotlin.resolve.calls.smartcasts.DataFlowValueFactory
 import org.jetbrains.kotlin.resolve.calls.smartcasts.DataFlowValueFactoryImpl
 import org.jetbrains.kotlin.types.KotlinType
 import org.jetbrains.kotlin.types.TypeUtils
@@ -28,20 +28,26 @@ fun calcProperTypeForIeee754ArithmeticIfNeeded(
     typeMapper: KotlinTypeMapper
 ): TypeAndNullability? {
     if (inferredPrimitiveType == null) return null
-    val ktType = expression.kotlinType(bindingContext) ?: return null
+    val ktType = expression.getKotlinTypeForComparison(bindingContext) ?: return null
     val isNullable = TypeUtils.isNullableType(ktType)
     val asmType = typeMapper.mapType(inferredPrimitiveType)
     if (!AsmUtil.isPrimitive(asmType)) return null
     return TypeAndNullability(asmType, isNullable)
 }
 
+private fun KtExpression.getKotlinTypeForComparison(bindingContext: BindingContext): KotlinType? =
+    when {
+        this is KtProperty -> bindingContext[BindingContext.VARIABLE, this]?.type
+        else -> kotlinType(bindingContext)
+    }
+
 fun legacyCalcTypeForIeee754ArithmeticIfNeeded(
     expression: KtExpression?,
     bindingContext: BindingContext,
     descriptor: DeclarationDescriptor,
     languageVersionSettings: LanguageVersionSettings
 ): TypeAndNullability? {
-    val ktType = expression.kotlinType(bindingContext) ?: return null
+    val ktType = expression?.getKotlinTypeForComparison(bindingContext) ?: return null
 
     if (KotlinBuiltIns.isDoubleOrNullableDouble(ktType)) {
         return TypeAndNullability(
@@ -59,7 +65,7 @@ fun legacyCalcTypeForIeee754ArithmeticIfNeeded(
 
     // NB. Using DataFlowValueFactoryImpl is a hack, but it is ok for 'legacy'
     val dataFlow = DataFlowValueFactoryImpl().createDataFlowValue(
-        expression!!,
+        expression,
         ktType,
         bindingContext,
         descriptor
diff --git a/compiler/testData/codegen/box/when/whenSubjectVariable/ieee754Equality.kt b/compiler/testData/codegen/box/when/whenSubjectVariable/ieee754Equality.kt
new file mode 100644
index 00000000000..49e4b5678f2
--- /dev/null
+++ b/compiler/testData/codegen/box/when/whenSubjectVariable/ieee754Equality.kt
@@ -0,0 +1,13 @@
+// !LANGUAGE: +VariableDeclarationInWhenSubject
+// IGNORE_BACKEND: JS
+
+val dz = -0.0
+
+fun box(): String {
+    when (val y = dz) {
+        0.0 -> {}
+        else -> throw AssertionError()
+    }
+
+    return "OK"
+}
\ No newline at end of file
diff --git a/compiler/testData/codegen/box/when/whenSubjectVariable/ieee754EqualityWithSmartCast.kt b/compiler/testData/codegen/box/when/whenSubjectVariable/ieee754EqualityWithSmartCast.kt
new file mode 100644
index 00000000000..56dca102979
--- /dev/null
+++ b/compiler/testData/codegen/box/when/whenSubjectVariable/ieee754EqualityWithSmartCast.kt
@@ -0,0 +1,14 @@
+// !LANGUAGE: +VariableDeclarationInWhenSubject +ProperIeee754Comparisons
+// IGNORE_BACKEND: JS
+
+val az: Any = -0.0
+
+fun box(): String {
+    when (val y = az) {
+        !is Double -> throw AssertionError()
+        0.0 -> {}
+        else -> throw AssertionError()
+    }
+
+    return "OK"
+}
\ No newline at end of file
diff --git a/compiler/tests-ir-jvm/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java b/compiler/tests-ir-jvm/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java
index 8f1d6201ecf..3f1ad85a3c9 100644
--- a/compiler/tests-ir-jvm/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java
+++ b/compiler/tests-ir-jvm/tests/org/jetbrains/kotlin/codegen/ir/IrBlackBoxCodegenTestGenerated.java
@@ -21673,6 +21673,16 @@ public class IrBlackBoxCodegenTestGenerated extends AbstractIrBlackBoxCodegenTes
                 runTest("compiler/testData/codegen/box/when/whenSubjectVariable/equalityWithSubjectVariable.kt");
             }
 
+            @TestMetadata("ieee754Equality.kt")
+            public void testIeee754Equality() throws Exception {
+                runTest("compiler/testData/codegen/box/when/whenSubjectVariable/ieee754Equality.kt");
+            }
+
+            @TestMetadata("ieee754EqualityWithSmartCast.kt")
+            public void testIeee754EqualityWithSmartCast() throws Exception {
+                runTest("compiler/testData/codegen/box/when/whenSubjectVariable/ieee754EqualityWithSmartCast.kt");
+            }
+
             @TestMetadata("isCheckOnSubjectVariable.kt")
             public void testIsCheckOnSubjectVariable() throws Exception {
                 runTest("compiler/testData/codegen/box/when/whenSubjectVariable/isCheckOnSubjectVariable.kt");
diff --git a/compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java b/compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java
index 01ceccda028..78c24942760 100644
--- a/compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/codegen/BlackBoxCodegenTestGenerated.java
@@ -21673,6 +21673,16 @@ public class BlackBoxCodegenTestGenerated extends AbstractBlackBoxCodegenTest {
                 runTest("compiler/testData/codegen/box/when/whenSubjectVariable/equalityWithSubjectVariable.kt");
             }
 
+            @TestMetadata("ieee754Equality.kt")
+            public void testIeee754Equality() throws Exception {
+                runTest("compiler/testData/codegen/box/when/whenSubjectVariable/ieee754Equality.kt");
+            }
+
+            @TestMetadata("ieee754EqualityWithSmartCast.kt")
+            public void testIeee754EqualityWithSmartCast() throws Exception {
+                runTest("compiler/testData/codegen/box/when/whenSubjectVariable/ieee754EqualityWithSmartCast.kt");
+            }
+
             @TestMetadata("isCheckOnSubjectVariable.kt")
             public void testIsCheckOnSubjectVariable() throws Exception {
                 runTest("compiler/testData/codegen/box/when/whenSubjectVariable/isCheckOnSubjectVariable.kt");
diff --git a/compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java b/compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
index 78208a8ecf8..2826f4b8bd2 100644
--- a/compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
+++ b/compiler/tests/org/jetbrains/kotlin/codegen/LightAnalysisModeTestGenerated.java
@@ -21673,6 +21673,16 @@ public class LightAnalysisModeTestGenerated extends AbstractLightAnalysisModeTes
                 runTest("compiler/testData/codegen/box/when/whenSubjectVariable/equalityWithSubjectVariable.kt");
             }
 
+            @TestMetadata("ieee754Equality.kt")
+            public void testIeee754Equality() throws Exception {
+                runTest("compiler/testData/codegen/box/when/whenSubjectVariable/ieee754Equality.kt");
+            }
+
+            @TestMetadata("ieee754EqualityWithSmartCast.kt")
+            public void testIeee754EqualityWithSmartCast() throws Exception {
+                runTest("compiler/testData/codegen/box/when/whenSubjectVariable/ieee754EqualityWithSmartCast.kt");
+            }
+
             @TestMetadata("isCheckOnSubjectVariable.kt")
             public void testIsCheckOnSubjectVariable() throws Exception {
                 runTest("compiler/testData/codegen/box/when/whenSubjectVariable/isCheckOnSubjectVariable.kt");
diff --git a/js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java b/js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java
index 4c453c75692..97d2f007ed4 100644
--- a/js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java
+++ b/js/js.tests/test/org/jetbrains/kotlin/js/test/semantics/JsCodegenBoxTestGenerated.java
@@ -19566,6 +19566,16 @@ public class JsCodegenBoxTestGenerated extends AbstractJsCodegenBoxTest {
                 runTest("compiler/testData/codegen/box/when/whenSubjectVariable/equalityWithSubjectVariable.kt");
             }
 
+            @TestMetadata("ieee754Equality.kt")
+            public void testIeee754Equality() throws Exception {
+                runTest("compiler/testData/codegen/box/when/whenSubjectVariable/ieee754Equality.kt");
+            }
+
+            @TestMetadata("ieee754EqualityWithSmartCast.kt")
+            public void testIeee754EqualityWithSmartCast() throws Exception {
+                runTest("compiler/testData/codegen/box/when/whenSubjectVariable/ieee754EqualityWithSmartCast.kt");
+            }
+
             @TestMetadata("isCheckOnSubjectVariable.kt")
             public void testIsCheckOnSubjectVariable() throws Exception {
                 runTest("compiler/testData/codegen/box/when/whenSubjectVariable/isCheckOnSubjectVariable.kt");