diff --git a/include/inttypes.h b/include/inttypes.h
index 0f1d4f4..e136b23 100644
--- a/include/inttypes.h
+++ b/include/inttypes.h
@@ -8,7 +8,12 @@
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP_INTTYPES_H
+// AIX system headers need inttypes.h to be re-enterable while _STD_TYPES_T
+// is defined until an inclusion of it without _STD_TYPES_T occurs, in which
+// case the header guard macro is defined.
+#if !defined(_AIX) || !defined(_STD_TYPES_T)
 #define _LIBCPP_INTTYPES_H
+#endif // _STD_TYPES_T
 
 /*
     inttypes.h synopsis
diff --git a/include/stdint.h b/include/stdint.h
index c892298..d7b6902 100644
--- a/include/stdint.h
+++ b/include/stdint.h
@@ -8,7 +8,12 @@
 //===----------------------------------------------------------------------===//
 
 #ifndef _LIBCPP_STDINT_H
+// AIX system headers need stdint.h to be re-enterable while _STD_TYPES_T
+// is defined until an inclusion of it without _STD_TYPES_T occurs, in which
+// case the header guard macro is defined.
+#if !defined(_AIX) || !defined(_STD_TYPES_T)
 #define _LIBCPP_STDINT_H
+#endif // _STD_TYPES_T
 
 /*
     stdint.h synopsis
diff --git a/test/std/depr/depr.c.headers/stdint_h.sh.cpp b/test/std/depr/depr.c.headers/stdint_h.sh.cpp
new file mode 100644
index 0000000..bcc8a11
--- /dev/null
+++ b/test/std/depr/depr.c.headers/stdint_h.sh.cpp
@@ -0,0 +1,268 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+// AIX system headers need stdint.h to be re-enterable when macro _STD_TYPES_T
+// is defined. This test case tests that after including sys/types.h which
+// defines macro _STD_TYPES_T, includes stdint.h, and then undefines
+// _STD_TYPES_T, stdint.h can be entered to get to macros like UINT32_MAX.
+//
+// REQUIRES: aix
+// RUN: %compile -c
+// RUN: %compile -c -D_XOPEN_SOURCE=700
+
+// test <stdint.h>
+//
+// Test that limits macros are available when <stdint.h> is included with
+// or without macro _XOPEN_SOURCE=700.
+
+#include <sys/types.h>
+#include <stdint.h>
+
+#ifndef INT8_MIN
+#error INT8_MIN not defined
+#endif
+
+#ifndef INT16_MIN
+#error INT16_MIN not defined
+#endif
+
+#ifndef INT32_MIN
+#error INT32_MIN not defined
+#endif
+
+#ifndef INT64_MIN
+#error INT64_MIN not defined
+#endif
+
+#ifndef INT8_MAX
+#error INT8_MAX not defined
+#endif
+
+#ifndef INT16_MAX
+#error INT16_MAX not defined
+#endif
+
+#ifndef INT32_MAX
+#error INT32_MAX not defined
+#endif
+
+#ifndef INT64_MAX
+#error INT64_MAX not defined
+#endif
+
+#ifndef UINT8_MAX
+#error UINT8_MAX not defined
+#endif
+
+#ifndef UINT16_MAX
+#error UINT16_MAX not defined
+#endif
+
+#ifndef UINT32_MAX
+#error UINT32_MAX not defined
+#endif
+
+#ifndef UINT64_MAX
+#error UINT64_MAX not defined
+#endif
+
+#ifndef INT_LEAST8_MIN
+#error INT_LEAST8_MIN not defined
+#endif
+
+#ifndef INT_LEAST16_MIN
+#error INT_LEAST16_MIN not defined
+#endif
+
+#ifndef INT_LEAST32_MIN
+#error INT_LEAST32_MIN not defined
+#endif
+
+#ifndef INT_LEAST64_MIN
+#error INT_LEAST64_MIN not defined
+#endif
+
+#ifndef INT_LEAST8_MAX
+#error INT_LEAST8_MAX not defined
+#endif
+
+#ifndef INT_LEAST16_MAX
+#error INT_LEAST16_MAX not defined
+#endif
+
+#ifndef INT_LEAST32_MAX
+#error INT_LEAST32_MAX not defined
+#endif
+
+#ifndef INT_LEAST64_MAX
+#error INT_LEAST64_MAX not defined
+#endif
+
+#ifndef UINT_LEAST8_MAX
+#error UINT_LEAST8_MAX not defined
+#endif
+
+#ifndef UINT_LEAST16_MAX
+#error UINT_LEAST16_MAX not defined
+#endif
+
+#ifndef UINT_LEAST32_MAX
+#error UINT_LEAST32_MAX not defined
+#endif
+
+#ifndef UINT_LEAST64_MAX
+#error UINT_LEAST64_MAX not defined
+#endif
+
+#ifndef INT_FAST8_MIN
+#error INT_FAST8_MIN not defined
+#endif
+
+#ifndef INT_FAST16_MIN
+#error INT_FAST16_MIN not defined
+#endif
+
+#ifndef INT_FAST32_MIN
+#error INT_FAST32_MIN not defined
+#endif
+
+#ifndef INT_FAST64_MIN
+#error INT_FAST64_MIN not defined
+#endif
+
+#ifndef INT_FAST8_MAX
+#error INT_FAST8_MAX not defined
+#endif
+
+#ifndef INT_FAST16_MAX
+#error INT_FAST16_MAX not defined
+#endif
+
+#ifndef INT_FAST32_MAX
+#error INT_FAST32_MAX not defined
+#endif
+
+#ifndef INT_FAST64_MAX
+#error INT_FAST64_MAX not defined
+#endif
+
+#ifndef UINT_FAST8_MAX
+#error UINT_FAST8_MAX not defined
+#endif
+
+#ifndef UINT_FAST16_MAX
+#error UINT_FAST16_MAX not defined
+#endif
+
+#ifndef UINT_FAST32_MAX
+#error UINT_FAST32_MAX not defined
+#endif
+
+#ifndef UINT_FAST64_MAX
+#error UINT_FAST64_MAX not defined
+#endif
+
+#ifndef INTPTR_MIN
+#error INTPTR_MIN not defined
+#endif
+
+#ifndef INTPTR_MAX
+#error INTPTR_MAX not defined
+#endif
+
+#ifndef UINTPTR_MAX
+#error UINTPTR_MAX not defined
+#endif
+
+#ifndef INTMAX_MIN
+#error INTMAX_MIN not defined
+#endif
+
+#ifndef INTMAX_MAX
+#error INTMAX_MAX not defined
+#endif
+
+#ifndef UINTMAX_MAX
+#error UINTMAX_MAX not defined
+#endif
+
+#ifndef PTRDIFF_MIN
+#error PTRDIFF_MIN not defined
+#endif
+
+#ifndef PTRDIFF_MAX
+#error PTRDIFF_MAX not defined
+#endif
+
+#ifndef SIG_ATOMIC_MIN
+#error SIG_ATOMIC_MIN not defined
+#endif
+
+#ifndef SIG_ATOMIC_MAX
+#error SIG_ATOMIC_MAX not defined
+#endif
+
+#ifndef SIZE_MAX
+#error SIZE_MAX not defined
+#endif
+
+#ifndef WCHAR_MIN
+#error WCHAR_MIN not defined
+#endif
+
+#ifndef WCHAR_MAX
+#error WCHAR_MAX not defined
+#endif
+
+#ifndef WINT_MIN
+#error WINT_MIN not defined
+#endif
+
+#ifndef WINT_MAX
+#error WINT_MAX not defined
+#endif
+
+#ifndef INT8_C
+#error INT8_C not defined
+#endif
+
+#ifndef INT16_C
+#error INT16_C not defined
+#endif
+
+#ifndef INT32_C
+#error INT32_C not defined
+#endif
+
+#ifndef INT64_C
+#error INT64_C not defined
+#endif
+
+#ifndef UINT8_C
+#error UINT8_C not defined
+#endif
+
+#ifndef UINT16_C
+#error UINT16_C not defined
+#endif
+
+#ifndef UINT32_C
+#error UINT32_C not defined
+#endif
+
+#ifndef UINT64_C
+#error UINT64_C not defined
+#endif
+
+#ifndef INTMAX_C
+#error INTMAX_C not defined
+#endif
+
+#ifndef UINTMAX_C
+#error UINTMAX_C not defined
+#endif