diff --git a/core/src/main/java/org/teavm/backend/c/generate/CodeGenerationVisitor.java b/core/src/main/java/org/teavm/backend/c/generate/CodeGenerationVisitor.java
index 8b76c9c8c..34fd40db9 100644
--- a/core/src/main/java/org/teavm/backend/c/generate/CodeGenerationVisitor.java
+++ b/core/src/main/java/org/teavm/backend/c/generate/CodeGenerationVisitor.java
@@ -1217,6 +1217,10 @@ public class CodeGenerationVisitor implements ExprVisitor, StatementVisitor {
         }
         writer.println(";");
 
+        if (context.isLongjmp()) {
+            writer.println("TEAVM_UNREACHABLE");
+        }
+
         popLocation(statement.getLocation());
     }
 
diff --git a/core/src/main/resources/org/teavm/backend/c/runtime.h b/core/src/main/resources/org/teavm/backend/c/runtime.h
index 2bbc0b3d7..0deac2877 100644
--- a/core/src/main/resources/org/teavm/backend/c/runtime.h
+++ b/core/src/main/resources/org/teavm/backend/c/runtime.h
@@ -418,6 +418,17 @@ inline static void* teavm_nullCheck(void* o) {
     }
     return o;
 }
+
+#ifdef __GNUC__
+    #define TEAVM_UNREACHABLE __builtin_unreachable();
+#endif
+#ifdef _MSC_VER
+    #define TEAVM_UNREACHABLE __assume(0);
+#endif
+#ifndef TEAVM_UNREACHABLE
+    #define TEAVM_UNREACHABLE return;
+#endif
+
 #else
 #define TEAVM_JUMP_SUPPORTED 0
 #define TEAVM_JUMP_TO_FRAME(frame, id)