diff --git a/clang/lib/AST/Interp/InterpBuiltin.cpp b/clang/lib/AST/Interp/InterpBuiltin.cpp
index 280aa39398c8e..5976d4c3e7131 100644
--- a/clang/lib/AST/Interp/InterpBuiltin.cpp
+++ b/clang/lib/AST/Interp/InterpBuiltin.cpp
@@ -660,6 +660,7 @@ bool InterpretBuiltin(InterpState &S, CodePtr OpPC, const Function *F,
     S.Stk.push<Boolean>(Boolean::from(S.inConstantContext()));
     break;
   case Builtin::BI__builtin_assume:
+  case Builtin::BI__assume:
     break;
   case Builtin::BI__builtin_strcmp:
     if (!interp__builtin_strcmp(S, OpPC, Frame))
diff --git a/clang/test/AST/Interp/builtins.cpp b/clang/test/AST/Interp/builtins.cpp
index 5e2ffe50f3740..06a22b16b2dcb 100644
--- a/clang/test/AST/Interp/builtins.cpp
+++ b/clang/test/AST/Interp/builtins.cpp
@@ -1,7 +1,7 @@
-// RUN: %clang_cc1 -fexperimental-new-constant-interpreter %s -verify
-// RUN: %clang_cc1 -fexperimental-new-constant-interpreter %s -S -emit-llvm -o - | FileCheck %s
-// RUN: %clang_cc1 -verify=ref %s -Wno-constant-evaluated
-// RUN: %clang_cc1 -verify=ref %s -Wno-constant-evaluated %s -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -fexperimental-new-constant-interpreter %s -verify -fms-extensions
+// RUN: %clang_cc1 -fexperimental-new-constant-interpreter %s -fms-extensions -S -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -verify=ref %s -Wno-constant-evaluated -fms-extensions
+// RUN: %clang_cc1 -verify=ref %s -Wno-constant-evaluated %s -fms-extensions -S -emit-llvm -o - | FileCheck %s
 
 // expected-no-diagnostics
 // ref-no-diagnostics
@@ -26,6 +26,8 @@ bool is_this_constant() {
 constexpr bool assume() {
   __builtin_assume(true);
   __builtin_assume(false);
+  __assume(1);
+  __assume(false);
   return true;
 }
 static_assert(assume(), "");