diff --git a/clang/lib/AST/Interp/Floating.h b/clang/lib/AST/Interp/Floating.h
index f98f49a7afb70..c997323837c1c 100644
--- a/clang/lib/AST/Interp/Floating.h
+++ b/clang/lib/AST/Interp/Floating.h
@@ -89,6 +89,7 @@ class Floating final {
   bool isNan() const { return F.isNaN(); }
   bool isInf() const { return F.isInfinity(); }
   bool isFinite() const { return F.isFinite(); }
+  bool isNormal() const { return F.isNormal(); }
 
   ComparisonCategoryResult compare(const Floating &RHS) const {
     llvm::APFloatBase::cmpResult CmpRes = F.compare(RHS.F);
diff --git a/clang/lib/AST/Interp/InterpBuiltin.cpp b/clang/lib/AST/Interp/InterpBuiltin.cpp
index 6fe9bc7628efe..8c71f2f016252 100644
--- a/clang/lib/AST/Interp/InterpBuiltin.cpp
+++ b/clang/lib/AST/Interp/InterpBuiltin.cpp
@@ -196,6 +196,15 @@ static bool interp__builtin_isfinite(InterpState &S, CodePtr OpPC,
   return true;
 }
 
+static bool interp__builtin_isnormal(InterpState &S, CodePtr OpPC,
+                                     const InterpFrame *Frame,
+                                     const Function *F) {
+  const Floating &Arg = S.Stk.peek<Floating>();
+
+  S.Stk.push<Integral<32, true>>(Integral<32, true>::from(Arg.isNormal()));
+  return true;
+}
+
 bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const Function *F) {
   InterpFrame *Frame = S.Current;
   APValue Dummy;
@@ -276,6 +285,10 @@ bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const Function *F) {
     if (interp__builtin_isfinite(S, OpPC, Frame, F))
       return Ret<PT_Sint32>(S, OpPC, Dummy);
     break;
+  case Builtin::BI__builtin_isnormal:
+    if (interp__builtin_isnormal(S, OpPC, Frame, F))
+      return Ret<PT_Sint32>(S, OpPC, Dummy);
+    break;
 
   default:
     return false;
diff --git a/clang/test/AST/Interp/builtin-functions.cpp b/clang/test/AST/Interp/builtin-functions.cpp
index 9457100a15f52..924914f9f942b 100644
--- a/clang/test/AST/Interp/builtin-functions.cpp
+++ b/clang/test/AST/Interp/builtin-functions.cpp
@@ -79,4 +79,7 @@ namespace inf {
 
   static_assert(__builtin_isfinite(1.0), "");
   static_assert(!__builtin_isfinite(__builtin_inf()), "");
+
+  static_assert(__builtin_isnormal(1.0), "");
+  static_assert(!__builtin_isnormal(__builtin_inf()), "");
 }