diff --git a/runtime/vm/compiler/assembler/assembler.h b/runtime/vm/compiler/assembler/assembler.h
index bc16cba..3eddf5d 100644
--- a/runtime/vm/compiler/assembler/assembler.h
+++ b/runtime/vm/compiler/assembler/assembler.h
@@ -24,7 +24,7 @@
 class AssemblerBuffer;
 class MemoryRegion;
 
-class Label : public ValueObject {
+class Label : public ZoneAllocated {
  public:
   Label() : position_(0), unresolved_(0) {
 #ifdef DEBUG
diff --git a/runtime/vm/compiler/backend/il_arm.cc b/runtime/vm/compiler/backend/il_arm.cc
index 36a33a2..7505abd 100644
--- a/runtime/vm/compiler/backend/il_arm.cc
+++ b/runtime/vm/compiler/backend/il_arm.cc
@@ -3372,6 +3372,12 @@
       __ b(instruction()->is_negated() ? labels_.true_label
                                        : labels_.false_label);
     } else {
+      if (instruction()->is_negated()) {
+        // Need to negate the result of slow path call.
+        __ CompareObject(result, Bool::True());
+        __ LoadObject(result, Bool::True(), NE);
+        __ LoadObject(result, Bool::False(), EQ);
+      }
       __ b(exit_label());
     }
   }
diff --git a/runtime/vm/compiler/backend/il_arm64.cc b/runtime/vm/compiler/backend/il_arm64.cc
index 6049bb7..5312520 100644
--- a/runtime/vm/compiler/backend/il_arm64.cc
+++ b/runtime/vm/compiler/backend/il_arm64.cc
@@ -3079,7 +3079,9 @@
            EQ);
       __ b(instruction()->is_negated() ? labels_.true_label
                                        : labels_.false_label);
+      ASSERT(exit_label()->IsUnused());
     } else {
+      ASSERT(!instruction()->is_negated());
       __ b(exit_label());
     }
   }
@@ -3138,28 +3140,38 @@
   Condition true_condition = EmitComparisonCode(compiler, labels);
   ASSERT(true_condition != kInvalidCondition);
   EmitBranchOnCondition(compiler, true_condition, labels);
-  __ Bind(slow_path->exit_label());
+  // No need to bind slow_path->exit_label() as slow path exits through
+  // true/false branch labels.
 }
 
 void CheckedSmiComparisonInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
-  Label true_label, false_label, done;
-  BranchLabels labels = {&true_label, &false_label, &false_label};
+  // Zone-allocate labels to pass them to slow-path which outlives local scope.
+  Label* true_label = new (Z) Label();
+  Label* false_label = new (Z) Label();
+  Label done;
+  BranchLabels labels = {true_label, false_label, false_label};
+  // In case of negated comparison result of a slow path call should be negated.
+  // For this purpose, 'merged' slow path is generated: it tests
+  // result of a call and jumps directly to true or false label.
   CheckedSmiComparisonSlowPath* slow_path = new CheckedSmiComparisonSlowPath(
       this, compiler->CurrentTryIndex(), labels,
-      /* merged = */ false);
+      /* merged = */ is_negated());
   compiler->AddSlowPathCode(slow_path);
   EMIT_SMI_CHECK;
   Condition true_condition = EmitComparisonCode(compiler, labels);
   ASSERT(true_condition != kInvalidCondition);
   EmitBranchOnCondition(compiler, true_condition, labels);
   Register result = locs()->out(0).reg();
-  __ Bind(&false_label);
+  __ Bind(false_label);
   __ LoadObject(result, Bool::False());
   __ b(&done);
-  __ Bind(&true_label);
+  __ Bind(true_label);
   __ LoadObject(result, Bool::True());
   __ Bind(&done);
-  __ Bind(slow_path->exit_label());
+  // In case of negated comparison slow path exits through true/false labels.
+  if (!is_negated()) {
+    __ Bind(slow_path->exit_label());
+  }
 }
 
 LocationSummary* BinarySmiOpInstr::MakeLocationSummary(Zone* zone,
diff --git a/runtime/vm/compiler/backend/il_x64.cc b/runtime/vm/compiler/backend/il_x64.cc
index 5c5658f..8365db6 100644
--- a/runtime/vm/compiler/backend/il_x64.cc
+++ b/runtime/vm/compiler/backend/il_x64.cc
@@ -2994,7 +2994,7 @@
   CheckedSmiComparisonSlowPath(CheckedSmiComparisonInstr* instruction,
                                intptr_t try_index,
                                BranchLabels labels,
-                               bool merged = false)
+                               bool merged)
       : TemplateSlowPathCode(instruction),
         try_index_(try_index),
         labels_(labels),
@@ -3033,7 +3033,9 @@
                                               : labels_.true_label);
       __ jmp(instruction()->is_negated() ? labels_.true_label
                                          : labels_.false_label);
+      ASSERT(exit_label()->IsUnused());
     } else {
+      ASSERT(!instruction()->is_negated());
       __ jmp(exit_label());
     }
   }
@@ -3093,28 +3095,38 @@
   Condition true_condition = EmitComparisonCode(compiler, labels);
   ASSERT(true_condition != INVALID_CONDITION);
   EmitBranchOnCondition(compiler, true_condition, labels);
-  __ Bind(slow_path->exit_label());
+  // No need to bind slow_path->exit_label() as slow path exits through
+  // true/false branch labels.
 }
 
 void CheckedSmiComparisonInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
-  Label true_label, false_label, done;
-  BranchLabels labels = {&true_label, &false_label, &false_label};
+  // Zone-allocate labels to pass them to slow-path which outlives local scope.
+  Label* true_label = new (Z) Label();
+  Label* false_label = new (Z) Label();
+  Label done;
+  BranchLabels labels = {true_label, false_label, false_label};
+  // In case of negated comparison result of a slow path call should be negated.
+  // For this purpose, 'merged' slow path is generated: it tests
+  // result of a call and jumps directly to true or false label.
   CheckedSmiComparisonSlowPath* slow_path = new CheckedSmiComparisonSlowPath(
       this, compiler->CurrentTryIndex(), labels,
-      /* merged = */ false);
+      /* merged = */ is_negated());
   compiler->AddSlowPathCode(slow_path);
   EMIT_SMI_CHECK;
   Condition true_condition = EmitComparisonCode(compiler, labels);
   ASSERT(true_condition != INVALID_CONDITION);
   EmitBranchOnCondition(compiler, true_condition, labels);
   Register result = locs()->out(0).reg();
-  __ Bind(&false_label);
+  __ Bind(false_label);
   __ LoadObject(result, Bool::False());
   __ jmp(&done);
-  __ Bind(&true_label);
+  __ Bind(true_label);
   __ LoadObject(result, Bool::True());
   __ Bind(&done);
-  __ Bind(slow_path->exit_label());
+  // In case of negated comparison slow path exits through true/false labels.
+  if (!is_negated()) {
+    __ Bind(slow_path->exit_label());
+  }
 }
 
 static bool CanBeImmediate(const Object& constant) {
diff --git a/tests/language_2/vm/regress_flutter_19612_test.dart b/tests/language_2/vm/regress_flutter_19612_test.dart
new file mode 100644
index 0000000..e7b3af1
--- /dev/null
+++ b/tests/language_2/vm/regress_flutter_19612_test.dart
@@ -0,0 +1,26 @@
+// Copyright (c) 2018, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+// Regression test for https://github.com/flutter/flutter/issues/19612.
+// This test verifies that negated condition is correctly handled by the
+// AOT compiler.
+
+import "package:expect/expect.dart";
+
+class X {
+  final int maxLines;
+  X([this.maxLines]);
+
+  bool get isMultiline => maxLines != 1;
+}
+
+X x1 = new X(1);
+X x2 = new X(42);
+X x3 = new X();
+
+main() {
+  Expect.isFalse(x1.isMultiline);
+  Expect.isTrue(x2.isMultiline);
+  Expect.isTrue(x3.isMultiline);
+}