From 5a42e2bc2805601939200ed8c68938b03634367d Mon Sep 17 00:00:00 2001
From: Dominic Chen <ddchen@apple.com>
Date: Wed, 17 Aug 2022 10:37:24 -0700
Subject: [PATCH] Revert "[libcxx] Resolve warnings for Wshift-sign-overflow"

This reverts commit 774c39313e83e8087776246c186593ea0c751fd5.
---
 libcxx/include/__chrono/duration.h         |  2 +-
 libcxx/include/__memory/temporary_buffer.h |  5 ++--
 libcxx/include/ratio                       | 30 +++++++++++-----------
 libcxx/utils/libcxx/test/params.py         |  1 -
 4 files changed, 19 insertions(+), 19 deletions(-)

diff --git a/libcxx/include/__chrono/duration.h b/libcxx/include/__chrono/duration.h
index 0f0e623af9e4..4345fffbc156 100644
--- a/libcxx/include/__chrono/duration.h
+++ b/libcxx/include/__chrono/duration.h
@@ -212,7 +212,7 @@ class _LIBCPP_TEMPLATE_VIS duration
         static const intmax_t __d1 = _R1::den / __gcd_d1_d2;
         static const intmax_t __n2 = _R2::num / __gcd_n1_n2;
         static const intmax_t __d2 = _R2::den / __gcd_d1_d2;
-        static const intmax_t max = numeric_limits<intmax_t>::max();
+        static const intmax_t max = -((intmax_t(1) << (sizeof(intmax_t) * CHAR_BIT - 1)) + 1);
 
         template <intmax_t _Xp, intmax_t _Yp, bool __overflow>
         struct __mul    // __overflow == false
diff --git a/libcxx/include/__memory/temporary_buffer.h b/libcxx/include/__memory/temporary_buffer.h
index 0b44bc4b6c90..c917f041a014 100644
--- a/libcxx/include/__memory/temporary_buffer.h
+++ b/libcxx/include/__memory/temporary_buffer.h
@@ -14,7 +14,6 @@
 #include <__type_traits/alignment_of.h>
 #include <__utility/pair.h>
 #include <cstddef>
-#include <limits>
 #include <new>
 
 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
@@ -29,7 +28,9 @@ pair<_Tp*, ptrdiff_t>
 get_temporary_buffer(ptrdiff_t __n) _NOEXCEPT
 {
     pair<_Tp*, ptrdiff_t> __r(0, 0);
-    const ptrdiff_t __m = (~ptrdiff_t(0) ^ numeric_limits<ptrdiff_t>::min()) / sizeof(_Tp);
+    const ptrdiff_t __m = (~ptrdiff_t(0) ^
+                           ptrdiff_t(ptrdiff_t(1) << (sizeof(ptrdiff_t) * __CHAR_BIT__ - 1)))
+                           / sizeof(_Tp);
     if (__n > __m)
         __n = __m;
     while (__n > 0)
diff --git a/libcxx/include/ratio b/libcxx/include/ratio
index 20e8e7f155b5..5d7af88a2ac8 100644
--- a/libcxx/include/ratio
+++ b/libcxx/include/ratio
@@ -79,8 +79,8 @@ typedef ratio<1000000000000000000000000, 1> yotta;  // not supported
 
 #include <__assert> // all public C++ headers provide the assertion handler
 #include <__config>
+#include <climits>
 #include <cstdint>
-#include <limits>
 #include <type_traits>
 #include <version>
 
@@ -140,8 +140,8 @@ class __ll_add;
 template <intmax_t _Xp, intmax_t _Yp>
 class __ll_add<_Xp, _Yp, 1>
 {
-    static const intmax_t min = numeric_limits<intmax_t>::min() + 1;
-    static const intmax_t max = numeric_limits<intmax_t>::max();
+    static const intmax_t min = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1)) + 1;
+    static const intmax_t max = -min;
 
     static_assert(_Xp <= max - _Yp, "overflow in __ll_add");
 public:
@@ -158,8 +158,8 @@ public:
 template <intmax_t _Xp, intmax_t _Yp>
 class __ll_add<_Xp, _Yp, -1>
 {
-    static const intmax_t min = numeric_limits<intmax_t>::min() + 1;
-    static const intmax_t max = numeric_limits<intmax_t>::max();
+    static const intmax_t min = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1)) + 1;
+    static const intmax_t max = -min;
 
     static_assert(min - _Yp <= _Xp, "overflow in __ll_add");
 public:
@@ -172,8 +172,8 @@ class __ll_sub;
 template <intmax_t _Xp, intmax_t _Yp>
 class __ll_sub<_Xp, _Yp, 1>
 {
-    static const intmax_t min = numeric_limits<intmax_t>::min() + 1;
-    static const intmax_t max = numeric_limits<intmax_t>::max();
+    static const intmax_t min = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1)) + 1;
+    static const intmax_t max = -min;
 
     static_assert(min + _Yp <= _Xp, "overflow in __ll_sub");
 public:
@@ -190,8 +190,8 @@ public:
 template <intmax_t _Xp, intmax_t _Yp>
 class __ll_sub<_Xp, _Yp, -1>
 {
-    static const intmax_t min = numeric_limits<intmax_t>::min() + 1;
-    static const intmax_t max = numeric_limits<intmax_t>::max();
+    static const intmax_t min = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1)) + 1;
+    static const intmax_t max = -min;
 
     static_assert(_Xp <= max + _Yp, "overflow in __ll_sub");
 public:
@@ -201,9 +201,9 @@ public:
 template <intmax_t _Xp, intmax_t _Yp>
 class __ll_mul
 {
-    static const intmax_t nan = numeric_limits<intmax_t>::min();
-    static const intmax_t min = numeric_limits<intmax_t>::min() + 1;
-    static const intmax_t max = numeric_limits<intmax_t>::max();
+    static const intmax_t nan = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1));
+    static const intmax_t min = nan + 1;
+    static const intmax_t max = -min;
     static const intmax_t __a_x = __static_abs<_Xp>::value;
     static const intmax_t __a_y = __static_abs<_Yp>::value;
 
@@ -237,9 +237,9 @@ public:
 template <intmax_t _Xp, intmax_t _Yp>
 class __ll_div
 {
-    static const intmax_t nan = numeric_limits<intmax_t>::min();
-    static const intmax_t min = numeric_limits<intmax_t>::min() + 1;
-    static const intmax_t max = numeric_limits<intmax_t>::max();
+    static const intmax_t nan = (1LL << (sizeof(intmax_t) * CHAR_BIT - 1));
+    static const intmax_t min = nan + 1;
+    static const intmax_t max = -min;
 
     static_assert(_Xp != nan && _Yp != nan && _Yp != 0, "overflow in __ll_div");
 public:
diff --git a/libcxx/utils/libcxx/test/params.py b/libcxx/utils/libcxx/test/params.py
index ebfbd13d815d..c46b55d0c6b3 100644
--- a/libcxx/utils/libcxx/test/params.py
+++ b/libcxx/utils/libcxx/test/params.py
@@ -15,7 +15,6 @@ _warningFlags = [
   '-Wall',
   '-Wextra',
   '-Wshadow',
-  '-Wshift-sign-overflow',
   '-Wundef',
   '-Wno-unused-command-line-argument',
   '-Wno-attributes',