Merge pull request #71736 from nate-chandler/add-missing-flag

Add missing guard around new builtin.

Author: nate-chandler

include/swift/Basic/Features.def

@@ -125,6 +125,7 @@ LANGUAGE_FEATURE(TypedThrows, 413, "Typed throws")
 LANGUAGE_FEATURE(OptionalIsolatedParameters, 420, "Optional isolated parameters")
 SUPPRESSIBLE_LANGUAGE_FEATURE(Extern, 0, "@_extern")
 LANGUAGE_FEATURE(ExpressionMacroDefaultArguments, 422, "Expression macro as caller-side default argument")
+LANGUAGE_FEATURE(BuiltinStoreRaw, 0, "Builtin.storeRaw")
 
 UPCOMING_FEATURE(ConciseMagicFile, 274, 6)
 UPCOMING_FEATURE(ForwardTrailingClosures, 286, 6)

lib/AST/ASTPrinter.cpp

@@ -3008,6 +3008,8 @@ static bool usesFeatureExpressionMacroDefaultArguments(Decl *decl) {
   return false;
 }
 
+static bool usesFeatureBuiltinStoreRaw(Decl *decl) { return false; }
+
 static bool usesFeatureCodeItemMacros(Decl *decl) {
   auto macro = dyn_cast<MacroDecl>(decl);
   if (!macro)

stdlib/public/core/UnsafeRawPointer.swift

@@ -1316,7 +1316,11 @@ public struct UnsafeMutableRawPointer: _Pointer {
   public func storeBytes<T : _BitwiseCopyable>(
     of value: T, toByteOffset offset: Int = 0, as type: T.Type
   ) {
+#if $BuiltinStoreRaw
     Builtin.storeRaw(value, (self + offset)._rawValue)
+#else
+    fatalError("Unsupported swift compiler!")
+#endif
   }
 #endif
   @inlinable