Implement constexpr std::vector

stl/inc/xmemory

@@ -1212,8 +1212,8 @@ private:
 
 // MEMBER FUNCTIONS FOR _Container_base12
 _CONSTEXPR20_CONTAINER void _Container_base12::_Orphan_all_unlocked() noexcept {
-    for (auto _Pnext = &_Myproxy->_Myfirstiter; *_Pnext; *_Pnext = (*_Pnext)->_Mynextiter) {
-        (*_Pnext)->_Myproxy = nullptr;
+    for (auto& _Pnext = _Myproxy->_Myfirstiter; _Pnext; _Pnext = _Pnext->_Mynextiter) { // TRANSITION, VSO-1269037
+        _Pnext->_Myproxy = nullptr;
     }
     _Myproxy->_Myfirstiter = nullptr;
 }

stl/inc/yvals_core.h

@@ -181,6 +181,7 @@
 // P0919R3 Heterogeneous Lookup For Unordered Containers
 // P0966R1 string::reserve() Should Not Shrink
 // P1001R2 execution::unseq
+// P1004R2 constexpr std::vector
 // P1006R1 constexpr For pointer_traits<T*>::pointer_to()
 // P1007R3 assume_aligned()
 // P1020R1 Smart Pointer Creation With Default Initialization
@@ -1202,6 +1203,10 @@
 #define __cpp_lib_constexpr_tuple       201811L
 #define __cpp_lib_constexpr_utility     201811L
 
+#if defined(__cpp_constexpr_dynamic_alloc) && !defined(__clang__) // TRANSITION, LLVM-48606
+#define __cpp_lib_constexpr_vector 201907L
+#endif // defined(__cpp_constexpr_dynamic_alloc) && !defined(__clang__)
+
 #ifdef __cpp_impl_coroutine // TRANSITION, Clang coroutine support
 #define __cpp_lib_coroutine 201902L
 #endif // __cpp_impl_coroutine
@@ -1284,7 +1289,7 @@
 #endif
 
 // Functions that became constexpr in C++20 via P0980R1 or P1004R2
-#if defined(__cpp_lib_constexpr_dynamic_alloc) && !defined(__clang__) // TRANSITION:LLVM-48606
+#if defined(__cpp_lib_constexpr_dynamic_alloc) && !defined(__clang__) // TRANSITION, LLVM-48606
 #define _CONSTEXPR20_CONTAINER constexpr
 #else
 #define _CONSTEXPR20_CONTAINER inline

tests/libcxx/expected_results.txt

@@ -320,9 +320,6 @@ std/language.support/support.limits/support.limits.general/functional.version.pa
 std/language.support/support.limits/support.limits.general/iterator.version.pass.cpp FAIL
 std/language.support/support.limits/support.limits.general/memory.version.pass.cpp FAIL
 
-# C++20 P1004R2 "constexpr std::vector"
-std/language.support/support.limits/support.limits.general/vector.version.pass.cpp FAIL
-
 # C++20 P1614R2 "Adding Spaceship <=> To The Library"
 std/language.support/support.limits/support.limits.general/compare.version.pass.cpp FAIL
 
@@ -373,6 +370,16 @@ std/utilities/utility/pairs/pairs.pair/assign_rv_pair_U_V.pass.cpp:0 FAIL
 std/algorithms/alg.sorting/alg.sort/partial.sort/partial_sort.pass.cpp:0 FAIL
 std/algorithms/alg.sorting/alg.sort/partial.sort/partial_sort_comp.pass.cpp:0 FAIL
 
+# VSO-1275530 "[constexpr] Temporaries created for functions do not have a ctor called (and have a redundant dtor)."
+std/numerics/numeric.ops/exclusive.scan/exclusive_scan.pass.cpp:0 FAIL
+std/numerics/numeric.ops/exclusive.scan/exclusive_scan_init_op.pass.cpp:0 FAIL
+std/numerics/numeric.ops/inclusive.scan/inclusive_scan.pass.cpp:0 FAIL
+std/numerics/numeric.ops/inclusive.scan/inclusive_scan_op.pass.cpp:0 FAIL
+std/numerics/numeric.ops/inclusive.scan/inclusive_scan_op_init.pass.cpp:0 FAIL
+std/numerics/numeric.ops/transform.exclusive.scan/transform_exclusive_scan_init_bop_uop.pass.cpp:0 FAIL
+std/numerics/numeric.ops/transform.inclusive.scan/transform_inclusive_scan_bop_uop.pass.cpp:0 FAIL
+std/numerics/numeric.ops/transform.inclusive.scan/transform_inclusive_scan_bop_uop_init.pass.cpp:0 FAIL
+
 
 # *** CLANG COMPILER BUGS ***
 # LLVM-33230 "Clang on Windows should define __STDCPP_THREADS__ to be 1"
@@ -381,6 +388,9 @@ std/thread/macro.pass.cpp:1 FAIL
 # LLVM-46207 Clang's tgmath.h interferes with the UCRT's tgmath.h
 std/depr/depr.c.headers/tgmath_h.pass.cpp:1 FAIL
 
+# LLVM-48606 "Clang rejects creation of struct with mutable member during constant evaluation"
+std/language.support/support.limits/support.limits.general/vector.version.pass.cpp:1 FAIL
+
 
 # *** CLANG ISSUES, NOT YET ANALYZED ***
 # Clang doesn't enable sized deallocation by default. Should we add -fsized-deallocation or do something else?

tests/libcxx/skipped_tests.txt

@@ -320,9 +320,6 @@ language.support\support.limits\support.limits.general\functional.version.pass.c
 language.support\support.limits\support.limits.general\iterator.version.pass.cpp
 language.support\support.limits\support.limits.general\memory.version.pass.cpp
 
-# C++20 P1004R2 "constexpr std::vector"
-language.support\support.limits\support.limits.general\vector.version.pass.cpp
-
 # C++20 P1614R2 "Adding Spaceship <=> To The Library"
 language.support\support.limits\support.limits.general\compare.version.pass.cpp
 
@@ -373,6 +370,16 @@ utilities\utility\pairs\pairs.pair\assign_rv_pair_U_V.pass.cpp
 algorithms\alg.sorting\alg.sort\partial.sort\partial_sort.pass.cpp
 algorithms\alg.sorting\alg.sort\partial.sort\partial_sort_comp.pass.cpp
 
+# VSO-1275530 "[constexpr] Temporaries created for functions do not have a ctor called (and have a redundant dtor)."
+numerics\numeric.ops\exclusive.scan\exclusive_scan.pass.cpp
+numerics\numeric.ops\exclusive.scan\exclusive_scan_init_op.pass.cpp
+numerics\numeric.ops\inclusive.scan\inclusive_scan.pass.cpp
+numerics\numeric.ops\inclusive.scan\inclusive_scan_op.pass.cpp
+numerics\numeric.ops\inclusive.scan\inclusive_scan_op_init.pass.cpp
+numerics\numeric.ops\transform.exclusive.scan\transform_exclusive_scan_init_bop_uop.pass.cpp
+numerics\numeric.ops\transform.inclusive.scan\transform_inclusive_scan_bop_uop.pass.cpp
+numerics\numeric.ops\transform.inclusive.scan\transform_inclusive_scan_bop_uop_init.pass.cpp
+
 
 # *** CLANG COMPILER BUGS ***
 # LLVM-33230 "Clang on Windows should define __STDCPP_THREADS__ to be 1"
@@ -381,6 +388,9 @@ thread\macro.pass.cpp
 # LLVM-46207 Clang's tgmath.h interferes with the UCRT's tgmath.h
 depr\depr.c.headers\tgmath_h.pass.cpp
 
+# LLVM-48606 "Clang rejects creation of struct with mutable member during constant evaluation"
+language.support\support.limits\support.limits.general\vector.version.pass.cpp
+
 
 # *** CLANG ISSUES, NOT YET ANALYZED ***
 # Clang doesn't enable sized deallocation by default. Should we add -fsized-deallocation or do something else?

tests/std/test.lst

@@ -260,6 +260,7 @@ tests\P0758R1_is_nothrow_convertible
 tests\P0768R1_spaceship_cpos
 tests\P0768R1_spaceship_operator
 tests\P0769R2_shift_left_shift_right
+tests\P0784R7_library_machinery
 tests\P0784R7_library_support_for_more_constexpr_containers
 tests\P0811R3_midpoint_lerp
 tests\P0896R4_common_iterator
@@ -379,6 +380,8 @@ tests\P0898R3_identity
 tests\P0912R5_coroutine
 tests\P0919R3_heterogeneous_unordered_lookup
 tests\P0966R1_string_reserve_should_not_shrink
+tests\P1004R2_constexpr_vector
+tests\P1004R2_constexpr_vector_bool
 tests\P1007R3_assume_aligned
 tests\P1020R1_smart_pointer_for_overwrite
 tests\P1023R0_constexpr_for_array_comparisons

tests/std/tests/Dev10_816787_swap_vector_bool_elements/test.cpp

@@ -17,6 +17,7 @@ int main() {
     assert(all_of(x.begin(), x.end(), is_false));
     assert(all_of(y.begin(), y.end(), is_true));
 
+#if !defined(__EDG__) || _ITERATOR_DEBUG_LEVEL != 2 // TRANSITION, VSO-1273381
     swap(x[12], y[34]);
 
     assert(all_of(x.begin(), x.begin() + 12, is_false));
@@ -26,4 +27,5 @@ int main() {
     assert(all_of(y.begin(), y.begin() + 34, is_true));
     assert(!y[34]);
     assert(all_of(y.begin() + 35, y.end(), is_true));
+#endif // !defined(__EDG__) || _ITERATOR_DEBUG_LEVEL != 2
 }

tests/std/tests/P0784R7_library_machinery/env.lst

@@ -0,0 +1,4 @@
+# Copyright (c) Microsoft Corporation.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+RUNALL_INCLUDE ..\usual_latest_matrix.lst

tests/std/tests/P0784R7_library_machinery/test.cpp

@@ -0,0 +1,150 @@
+// Copyright (c) Microsoft Corporation.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+#include <algorithm>
+#include <assert.h>
+#include <iterator>
+#include <memory>
+#include <type_traits>
+#include <utility>
+
+#pragma warning(disable : 4582) // '%s': constructor is not implicitly called
+#pragma warning(disable : 4583) // '%s': destructor is not implicitly called
+
+using namespace std;
+
+struct int_wrapper_copy {
+    constexpr int_wrapper_copy() = default;
+    constexpr int_wrapper_copy(const int v) : _val(v) {}
+
+    constexpr int_wrapper_copy(const int_wrapper_copy& other) : _val(other._val) {}
+    constexpr int_wrapper_copy& operator=(const int_wrapper_copy& other) {
+        _val = other._val;
+        return *this;
+    }
+
+    int_wrapper_copy(int_wrapper_copy&&) = delete;
+    int_wrapper_copy& operator=(int_wrapper_copy&&) = delete;
+
+    constexpr bool operator==(const int_wrapper_copy&) const = default;
+
+    int _val = 0;
+};
+
+struct int_wrapper_move {
+    constexpr int_wrapper_move() = default;
+    constexpr int_wrapper_move(const int v) : _val(v) {}
+
+    int_wrapper_move(const int_wrapper_move&) = delete;
+    int_wrapper_move& operator=(const int_wrapper_move&) = delete;
+
+    constexpr int_wrapper_move(int_wrapper_move&& other) : _val(exchange(other._val, -1)) {}
+    constexpr int_wrapper_move& operator=(int_wrapper_move&& other) {
+        _val = exchange(other._val, -1);
+        return *this;
+    }
+
+    constexpr bool operator==(const int_wrapper_move&) const = default;
+
+    int _val = 0;
+};
+
+static constexpr int_wrapper_copy expected_copy[]       = {1, 2, 3, 4};
+static constexpr int_wrapper_move expected_move[]       = {1, 2, 3, 4};
+static constexpr int_wrapper_move expected_after_move[] = {-1, -1, -1, -1};
+
+_CONSTEXPR20_DYNALLOC bool test() {
+    { // _Copy_unchecked
+        int_wrapper_copy input[]   = {1, 2, 3, 4};
+        int_wrapper_copy output[4] = {5, 6, 7, 8};
+
+        const auto result = _Copy_unchecked(begin(input), end(input), begin(output));
+        static_assert(is_same_v<remove_const_t<decltype(result)>, int_wrapper_copy*>);
+        assert(result == end(output));
+        assert(equal(begin(expected_copy), end(expected_copy), begin(output), end(output)));
+    }
+
+    { // _Copy_backward_unchecked
+        int_wrapper_copy input[]   = {1, 2, 3, 4};
+        int_wrapper_copy output[4] = {5, 6, 7, 8};
+
+        const auto result = _Copy_backward_unchecked(begin(input), end(input), end(output));
+        static_assert(is_same_v<remove_const_t<decltype(result)>, int_wrapper_copy*>);
+        assert(result == begin(output));
+        assert(equal(begin(expected_copy), end(expected_copy), begin(output), end(output)));
+    }
+
+#if defined(__cpp_constexpr_dynamic_alloc)
+    { // _Uninitialized_copy_unchecked
+        int_wrapper_copy input[] = {1, 2, 3, 4};
+        int_wrapper_copy output[4];
+
+        const auto result = _Uninitialized_copy_unchecked(begin(input), end(input), begin(output));
+        static_assert(is_same_v<remove_const_t<decltype(result)>, int_wrapper_copy*>);
+        assert(result == end(output));
+        assert(equal(begin(expected_copy), end(expected_copy), begin(output), end(output)));
+    }
+#endif // defined(__cpp_constexpr_dynamic_alloc)
+
+    { // _Move_unchecked
+        int_wrapper_move input[]   = {1, 2, 3, 4};
+        int_wrapper_move output[4] = {5, 6, 7, 8};
+
+        const auto result = _Move_unchecked(begin(input), end(input), begin(output));
+        static_assert(is_same_v<remove_const_t<decltype(result)>, int_wrapper_move*>);
+        assert(result == end(output));
+        assert(equal(begin(expected_move), end(expected_move), begin(output), end(output)));
+        if (is_constant_evaluated()) {
+            assert(equal(begin(input), end(input), begin(expected_after_move), end(expected_after_move)));
+        }
+    }
+
+    { // _Move_backward_unchecked
+        int_wrapper_move input[]   = {1, 2, 3, 4};
+        int_wrapper_move output[4] = {5, 6, 7, 8};
+
+        const auto result = _Move_backward_unchecked(begin(input), end(input), end(output));
+        static_assert(is_same_v<remove_const_t<decltype(result)>, int_wrapper_move*>);
+        assert(result == begin(output));
+        assert(equal(begin(expected_move), end(expected_move), begin(output), end(output)));
+        if (is_constant_evaluated()) {
+            assert(equal(begin(input), end(input), begin(expected_after_move), end(expected_after_move)));
+        }
+    }
+
+#ifdef __cpp_lib_concepts
+    { // _Move_backward_common
+        int_wrapper_move input[]   = {1, 2, 3, 4};
+        int_wrapper_move output[4] = {5, 6, 7, 8};
+
+        const auto result = ranges::_Move_backward_common(begin(input), end(input), end(output));
+        static_assert(is_same_v<remove_const_t<decltype(result)>, int_wrapper_move*>);
+        assert(result == begin(output));
+        assert(equal(begin(expected_move), end(expected_move), begin(output), end(output)));
+        if (is_constant_evaluated()) {
+            assert(equal(begin(input), end(input), begin(expected_after_move), end(expected_after_move)));
+        }
+    }
+#endif // __cpp_lib_concepts
+
+#if defined(__cpp_constexpr_dynamic_alloc) && (defined(__clang__) || defined(__EDG__)) // TRANSITION, DevCom-1333853
+    { // _Uninitialized_move_unchecked
+        int_wrapper_move input[] = {1, 2, 3, 4};
+        int_wrapper_move output[4];
+
+        const auto result = _Uninitialized_move_unchecked(begin(input), end(input), begin(output));
+        static_assert(is_same_v<remove_const_t<decltype(result)>, int_wrapper_move*>);
+        assert(result == end(output));
+        assert(equal(begin(expected_move), end(expected_move), begin(output), end(output)));
+        if (is_constant_evaluated()) {
+            assert(equal(begin(input), end(input), begin(expected_after_move), end(expected_after_move)));
+        }
+    }
+#endif // defined(__cpp_constexpr_dynamic_alloc) && (defined(__clang__) || defined(__EDG__))
+    return true;
+}
+
+int main() {
+    test();
+    static_assert(test());
+}

tests/std/tests/P1004R2_constexpr_vector/env.lst

@@ -0,0 +1,4 @@
+# Copyright (c) Microsoft Corporation.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+RUNALL_INCLUDE ..\usual_latest_matrix.lst