[clang] [libcxx] [clang] Add builtin to clear padding bytes (prework for P0528R3) (PR #75371)

[Eli Friedman via cfe-commits]

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@@ -0,0 +1,807 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+// UNSUPPORTED: c++03
----------------
efriedma-quic wrote:

There is no mechanism for clang/ tests to run on target.  Usually, if we think it's important, we add tests to SingleSource/UnitTests in llvm-test-suite.  But usually we just rely on clang regression testing.

https://github.com/llvm/llvm-project/pull/75371