diff --git a/compiler/optimizing/instruction_simplifier.cc b/compiler/optimizing/instruction_simplifier.cc
index a48d06f..c448153 100644
--- a/compiler/optimizing/instruction_simplifier.cc
+++ b/compiler/optimizing/instruction_simplifier.cc
@@ -92,6 +92,7 @@
   void SimplifySystemArrayCopy(HInvoke* invoke);
   void SimplifyStringEquals(HInvoke* invoke);
   void SimplifyCompare(HInvoke* invoke, bool has_zero_op);
+  void SimplifyIsNaN(HInvoke* invoke);
 
   OptimizingCompilerStats* stats_;
   bool simplification_occurred_ = false;
@@ -1551,6 +1552,15 @@
   invoke->GetBlock()->ReplaceAndRemoveInstructionWith(invoke, compare);
 }
 
+void InstructionSimplifierVisitor::SimplifyIsNaN(HInvoke* invoke) {
+  DCHECK(invoke->IsInvokeStaticOrDirect());
+  uint32_t dex_pc = invoke->GetDexPc();
+  // IsNaN(x) is the same as x != x.
+  HInstruction* x = invoke->InputAt(0);
+  HCondition* condition = new (GetGraph()->GetArena()) HNotEqual(x, x, dex_pc);
+  invoke->GetBlock()->ReplaceAndRemoveInstructionWith(invoke, condition);
+}
+
 void InstructionSimplifierVisitor::VisitInvoke(HInvoke* instruction) {
   if (instruction->GetIntrinsic() == Intrinsics::kStringEquals) {
     SimplifyStringEquals(instruction);
@@ -1568,6 +1578,9 @@
   } else if (instruction->GetIntrinsic() == Intrinsics::kIntegerSignum ||
              instruction->GetIntrinsic() == Intrinsics::kLongSignum) {
     SimplifyCompare(instruction, /* is_signum */ true);
+  } else if (instruction->GetIntrinsic() == Intrinsics::kFloatIsNaN ||
+             instruction->GetIntrinsic() == Intrinsics::kDoubleIsNaN) {
+    SimplifyIsNaN(instruction);
   }
 }
 
diff --git a/compiler/optimizing/intrinsics_arm.cc b/compiler/optimizing/intrinsics_arm.cc
index 00a158b..ea8669f 100644
--- a/compiler/optimizing/intrinsics_arm.cc
+++ b/compiler/optimizing/intrinsics_arm.cc
@@ -1858,8 +1858,6 @@
 
 UNIMPLEMENTED_INTRINSIC(FloatIsInfinite)
 UNIMPLEMENTED_INTRINSIC(DoubleIsInfinite)
-UNIMPLEMENTED_INTRINSIC(FloatIsNaN)
-UNIMPLEMENTED_INTRINSIC(DoubleIsNaN)
 
 UNIMPLEMENTED_INTRINSIC(IntegerHighestOneBit)
 UNIMPLEMENTED_INTRINSIC(LongHighestOneBit)
@@ -1867,6 +1865,8 @@
 UNIMPLEMENTED_INTRINSIC(LongLowestOneBit)
 
 // Handled as HIR instructions.
+UNIMPLEMENTED_INTRINSIC(FloatIsNaN)
+UNIMPLEMENTED_INTRINSIC(DoubleIsNaN)
 UNIMPLEMENTED_INTRINSIC(IntegerRotateLeft)
 UNIMPLEMENTED_INTRINSIC(LongRotateLeft)
 UNIMPLEMENTED_INTRINSIC(IntegerRotateRight)
diff --git a/compiler/optimizing/intrinsics_arm64.cc b/compiler/optimizing/intrinsics_arm64.cc
index 4140d94..8741fd2 100644
--- a/compiler/optimizing/intrinsics_arm64.cc
+++ b/compiler/optimizing/intrinsics_arm64.cc
@@ -1618,8 +1618,6 @@
 
 UNIMPLEMENTED_INTRINSIC(FloatIsInfinite)
 UNIMPLEMENTED_INTRINSIC(DoubleIsInfinite)
-UNIMPLEMENTED_INTRINSIC(FloatIsNaN)
-UNIMPLEMENTED_INTRINSIC(DoubleIsNaN)
 
 UNIMPLEMENTED_INTRINSIC(IntegerHighestOneBit)
 UNIMPLEMENTED_INTRINSIC(LongHighestOneBit)
@@ -1627,6 +1625,8 @@
 UNIMPLEMENTED_INTRINSIC(LongLowestOneBit)
 
 // Handled as HIR instructions.
+UNIMPLEMENTED_INTRINSIC(FloatIsNaN)
+UNIMPLEMENTED_INTRINSIC(DoubleIsNaN)
 UNIMPLEMENTED_INTRINSIC(IntegerRotateLeft)
 UNIMPLEMENTED_INTRINSIC(LongRotateLeft)
 UNIMPLEMENTED_INTRINSIC(IntegerRotateRight)
diff --git a/compiler/optimizing/intrinsics_mips.cc b/compiler/optimizing/intrinsics_mips.cc
index 2294713..e93b939 100644
--- a/compiler/optimizing/intrinsics_mips.cc
+++ b/compiler/optimizing/intrinsics_mips.cc
@@ -1016,8 +1016,6 @@
 
 UNIMPLEMENTED_INTRINSIC(FloatIsInfinite)
 UNIMPLEMENTED_INTRINSIC(DoubleIsInfinite)
-UNIMPLEMENTED_INTRINSIC(FloatIsNaN)
-UNIMPLEMENTED_INTRINSIC(DoubleIsNaN)
 
 UNIMPLEMENTED_INTRINSIC(IntegerHighestOneBit)
 UNIMPLEMENTED_INTRINSIC(LongHighestOneBit)
@@ -1025,6 +1023,8 @@
 UNIMPLEMENTED_INTRINSIC(LongLowestOneBit)
 
 // Handled as HIR instructions.
+UNIMPLEMENTED_INTRINSIC(FloatIsNaN)
+UNIMPLEMENTED_INTRINSIC(DoubleIsNaN)
 UNIMPLEMENTED_INTRINSIC(IntegerCompare)
 UNIMPLEMENTED_INTRINSIC(LongCompare)
 UNIMPLEMENTED_INTRINSIC(IntegerSignum)
diff --git a/compiler/optimizing/intrinsics_mips64.cc b/compiler/optimizing/intrinsics_mips64.cc
index ac28503..cf3a365 100644
--- a/compiler/optimizing/intrinsics_mips64.cc
+++ b/compiler/optimizing/intrinsics_mips64.cc
@@ -1764,8 +1764,6 @@
 
 UNIMPLEMENTED_INTRINSIC(FloatIsInfinite)
 UNIMPLEMENTED_INTRINSIC(DoubleIsInfinite)
-UNIMPLEMENTED_INTRINSIC(FloatIsNaN)
-UNIMPLEMENTED_INTRINSIC(DoubleIsNaN)
 
 UNIMPLEMENTED_INTRINSIC(IntegerHighestOneBit)
 UNIMPLEMENTED_INTRINSIC(LongHighestOneBit)
@@ -1773,6 +1771,8 @@
 UNIMPLEMENTED_INTRINSIC(LongLowestOneBit)
 
 // Handled as HIR instructions.
+UNIMPLEMENTED_INTRINSIC(FloatIsNaN)
+UNIMPLEMENTED_INTRINSIC(DoubleIsNaN)
 UNIMPLEMENTED_INTRINSIC(IntegerCompare)
 UNIMPLEMENTED_INTRINSIC(LongCompare)
 UNIMPLEMENTED_INTRINSIC(IntegerSignum)
diff --git a/compiler/optimizing/intrinsics_x86.cc b/compiler/optimizing/intrinsics_x86.cc
index 22cefe8..260a877 100644
--- a/compiler/optimizing/intrinsics_x86.cc
+++ b/compiler/optimizing/intrinsics_x86.cc
@@ -2635,8 +2635,6 @@
 
 UNIMPLEMENTED_INTRINSIC(FloatIsInfinite)
 UNIMPLEMENTED_INTRINSIC(DoubleIsInfinite)
-UNIMPLEMENTED_INTRINSIC(FloatIsNaN)
-UNIMPLEMENTED_INTRINSIC(DoubleIsNaN)
 
 UNIMPLEMENTED_INTRINSIC(IntegerHighestOneBit)
 UNIMPLEMENTED_INTRINSIC(LongHighestOneBit)
@@ -2644,6 +2642,8 @@
 UNIMPLEMENTED_INTRINSIC(LongLowestOneBit)
 
 // Handled as HIR instructions.
+UNIMPLEMENTED_INTRINSIC(FloatIsNaN)
+UNIMPLEMENTED_INTRINSIC(DoubleIsNaN)
 UNIMPLEMENTED_INTRINSIC(IntegerRotateLeft)
 UNIMPLEMENTED_INTRINSIC(LongRotateLeft)
 UNIMPLEMENTED_INTRINSIC(IntegerRotateRight)
diff --git a/compiler/optimizing/intrinsics_x86_64.cc b/compiler/optimizing/intrinsics_x86_64.cc
index c9a4344..93e8c00 100644
--- a/compiler/optimizing/intrinsics_x86_64.cc
+++ b/compiler/optimizing/intrinsics_x86_64.cc
@@ -2717,10 +2717,10 @@
 
 UNIMPLEMENTED_INTRINSIC(FloatIsInfinite)
 UNIMPLEMENTED_INTRINSIC(DoubleIsInfinite)
-UNIMPLEMENTED_INTRINSIC(FloatIsNaN)
-UNIMPLEMENTED_INTRINSIC(DoubleIsNaN)
 
 // Handled as HIR instructions.
+UNIMPLEMENTED_INTRINSIC(FloatIsNaN)
+UNIMPLEMENTED_INTRINSIC(DoubleIsNaN)
 UNIMPLEMENTED_INTRINSIC(IntegerRotateLeft)
 UNIMPLEMENTED_INTRINSIC(LongRotateLeft)
 UNIMPLEMENTED_INTRINSIC(IntegerRotateRight)
diff --git a/test/575-checker-isnan/expected.txt b/test/575-checker-isnan/expected.txt
new file mode 100644
index 0000000..b0aad4d
--- /dev/null
+++ b/test/575-checker-isnan/expected.txt
@@ -0,0 +1 @@
+passed
diff --git a/test/575-checker-isnan/info.txt b/test/575-checker-isnan/info.txt
new file mode 100644
index 0000000..5c48a6a
--- /dev/null
+++ b/test/575-checker-isnan/info.txt
@@ -0,0 +1 @@
+Unit test for float/double isNaN() operation.
diff --git a/test/575-checker-isnan/src/Main.java b/test/575-checker-isnan/src/Main.java
new file mode 100644
index 0000000..cc71e5e
--- /dev/null
+++ b/test/575-checker-isnan/src/Main.java
@@ -0,0 +1,126 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+public class Main {
+
+  /// CHECK-START: boolean Main.isNaN32(float) instruction_simplifier (before)
+  /// CHECK-DAG: <<Result:z\d+>> InvokeStaticOrDirect
+  /// CHECK-DAG: Return [<<Result>>]
+  //
+  /// CHECK-START: boolean Main.isNaN32(float) instruction_simplifier (after)
+  /// CHECK-DAG: <<Result:z\d+>> NotEqual
+  /// CHECK-DAG: Return [<<Result>>]
+  //
+  /// CHECK-START: boolean Main.isNaN32(float) instruction_simplifier (after)
+  /// CHECK-NOT: InvokeStaticOrDirect
+  private static boolean isNaN32(float x) {
+    return Float.isNaN(x);
+  }
+
+  /// CHECK-START: boolean Main.isNaN64(double) instruction_simplifier (before)
+  /// CHECK-DAG: <<Result:z\d+>> InvokeStaticOrDirect
+  /// CHECK-DAG: Return [<<Result>>]
+  //
+  /// CHECK-START: boolean Main.isNaN64(double) instruction_simplifier (after)
+  /// CHECK-DAG: <<Result:z\d+>> NotEqual
+  /// CHECK-DAG: Return [<<Result>>]
+  //
+  /// CHECK-START: boolean Main.isNaN64(double) instruction_simplifier (after)
+  /// CHECK-NOT: InvokeStaticOrDirect
+  private static boolean isNaN64(double x) {
+    return Double.isNaN(x);
+  }
+
+  public static void main(String args[]) {
+    // A few distinct numbers.
+    expectFalse(isNaN32(Float.NEGATIVE_INFINITY));
+    expectFalse(isNaN32(-1.0f));
+    expectFalse(isNaN32(-0.0f));
+    expectFalse(isNaN32(0.0f));
+    expectFalse(isNaN32(1.0f));
+    expectFalse(isNaN32(Float.POSITIVE_INFINITY));
+
+    // A few distinct subnormal numbers.
+    expectFalse(isNaN32(Float.intBitsToFloat(0x00400000)));
+    expectFalse(isNaN32(Float.intBitsToFloat(0x80400000)));
+    expectFalse(isNaN32(Float.intBitsToFloat(0x00000001)));
+    expectFalse(isNaN32(Float.intBitsToFloat(0x80000001)));
+
+    // A few NaN numbers.
+    expectTrue(isNaN32(Float.NaN));
+    expectTrue(isNaN32(0.0f / 0.0f));
+    expectTrue(isNaN32((float)Math.sqrt(-1.0f)));
+    float[] fvals = {
+      Float.intBitsToFloat(0x7f800001),
+      Float.intBitsToFloat(0x7fa00000),
+      Float.intBitsToFloat(0x7fc00000),
+      Float.intBitsToFloat(0x7fffffff),
+      Float.intBitsToFloat(0xff800001),
+      Float.intBitsToFloat(0xffa00000),
+      Float.intBitsToFloat(0xffc00000),
+      Float.intBitsToFloat(0xffffffff)
+    };
+    for (int i = 0; i < fvals.length; i++) {
+      expectTrue(isNaN32(fvals[i]));
+    }
+
+    // A few distinct numbers.
+    expectFalse(isNaN64(Double.NEGATIVE_INFINITY));
+    expectFalse(isNaN32(-1.0f));
+    expectFalse(isNaN64(-0.0d));
+    expectFalse(isNaN64(0.0d));
+    expectFalse(isNaN64(1.0d));
+    expectFalse(isNaN64(Double.POSITIVE_INFINITY));
+
+    // A few distinct subnormal numbers.
+    expectFalse(isNaN64(Double.longBitsToDouble(0x0008000000000000l)));
+    expectFalse(isNaN64(Double.longBitsToDouble(0x8008000000000000l)));
+    expectFalse(isNaN64(Double.longBitsToDouble(0x0000000000000001l)));
+    expectFalse(isNaN64(Double.longBitsToDouble(0x8000000000000001l)));
+
+    // A few NaN numbers.
+    expectTrue(isNaN64(Double.NaN));
+    expectTrue(isNaN64(0.0d / 0.0d));
+    expectTrue(isNaN64(Math.sqrt(-1.0d)));
+    double[] dvals = {
+      Double.longBitsToDouble(0x7ff0000000000001L),
+      Double.longBitsToDouble(0x7ff4000000000000L),
+      Double.longBitsToDouble(0x7ff8000000000000L),
+      Double.longBitsToDouble(0x7fffffffffffffffL),
+      Double.longBitsToDouble(0xfff0000000000001L),
+      Double.longBitsToDouble(0xfff4000000000000L),
+      Double.longBitsToDouble(0xfff8000000000000L),
+      Double.longBitsToDouble(0xffffffffffffffffL)
+    };
+    for (int i = 0; i < dvals.length; i++) {
+      expectTrue(isNaN64(dvals[i]));
+    }
+
+    System.out.println("passed");
+  }
+
+  private static void expectTrue(boolean value) {
+    if (!value) {
+      throw new Error("Expected True");
+    }
+  }
+
+  private static void expectFalse(boolean value) {
+    if (value) {
+      throw new Error("Expected False");
+    }
+  }
+}