From: Jonathan Wakely <jwakely@redhat.com>
To: libstdc++@gcc.gnu.org, gcc-patches@gcc.gnu.org
Subject: Re: [committed 7/8] libstdc++: Update (and revert) value of __cpp_lib_array_constexpr
Date: Thu, 23 Apr 2020 21:44:17 +0100 [thread overview]
Message-ID: <20200423204417.GR71320@redhat.com> (raw)
In-Reply-To: <e851aa1703c3d911720d8f9bee68a521abe588f7.1587592482.git.jwakely@redhat.com>
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On 22/04/20 22:59 +0100, Jonathan Wakely wrote:
>This macro should have been updated to 201811 when the last C++20
>changes were implemented. However those changes are not enabled for
>C++17 mode, so the macro should only have the new value in C++20 mode.
>
>This change ensures that the macro is defined to 201603 for C++17 and
>201811 for C++20.
>
> * include/bits/stl_iterator.h (__cpp_lib_array_constexpr): Define
> different values for C++17 and C++20, to indicate different feature
> sets. Update value for C++20 to indicate P1032R1 support.
> * include/std/version (__cpp_lib_array_constexpr): Likewise.
> * testsuite/23_containers/array/comparison_operators/constexpr.cc:
> Check feature test macro.
> * testsuite/23_containers/array/element_access/constexpr_c++17.cc:
> New test.
> * testsuite/23_containers/array/requirements/constexpr_fill.cc: Check
> feature test macro.
> * testsuite/23_containers/array/requirements/constexpr_iter.cc: Test
> in C++17 mode and check feature test macro.
On second thoughts, changing __cpp_lib_array_constexpr for C++17 was
wrong, it should have been left at 201803.
This partially reverts my previous change related to this macro. The
C++20 constexpr iterator requirements are always met by array:iterator,
because it's just a pointer. So the macro can be set to 201803 even in
C++17 mode.
Tested powerpc64le-linux, committed to master.
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commit 40541efe1c063e9ce894b5f11ff727e4aec56e8b
Author: Jonathan Wakely <jwakely@redhat.com>
Date: Thu Apr 23 21:39:33 2020 +0100
libstdc++: Change __cpp_lib_array_constexpr for C++17 again
This partially reverts my previous change related to this macro. The
C++20 constexpr iterator requirements are always met by array:iterator,
because it's just a pointer. So the macro can be set to 201803 even in
C++17 mode.
* include/bits/stl_iterator.h (__cpp_lib_array_constexpr): Revert
value for C++17 to 201803L because P0858R0 is supported for C++17.
* include/std/version (__cpp_lib_array_constexpr): Likewise.
* testsuite/23_containers/array/element_access/constexpr_c++17.cc:
Check for value corresponding to P0031R0 features being tested.
* testsuite/23_containers/array/requirements/constexpr_iter.cc:
Check for value corresponding to P0858R0 features being tested.
diff --git a/libstdc++-v3/include/bits/stl_iterator.h b/libstdc++-v3/include/bits/stl_iterator.h
index d7e85b84041..cc0b3e0a766 100644
--- a/libstdc++-v3/include/bits/stl_iterator.h
+++ b/libstdc++-v3/include/bits/stl_iterator.h
@@ -72,7 +72,7 @@
#if __cplusplus > 201703L
# define __cpp_lib_array_constexpr 201811L
#elif __cplusplus == 201703L
-# define __cpp_lib_array_constexpr 201603L
+# define __cpp_lib_array_constexpr 201803L
#endif
#if __cplusplus > 201703L
diff --git a/libstdc++-v3/include/std/version b/libstdc++-v3/include/std/version
index 1beb9aa938e..fa505f25e98 100644
--- a/libstdc++-v3/include/std/version
+++ b/libstdc++-v3/include/std/version
@@ -123,7 +123,7 @@
#if _GLIBCXX_HOSTED
#define __cpp_lib_any 201606L
#define __cpp_lib_apply 201603
-#define __cpp_lib_array_constexpr 201603L
+#define __cpp_lib_array_constexpr 201803L
#define __cpp_lib_as_const 201510
#define __cpp_lib_boyer_moore_searcher 201603
#define __cpp_lib_chrono 201611
diff --git a/libstdc++-v3/testsuite/23_containers/array/element_access/constexpr_c++17.cc b/libstdc++-v3/testsuite/23_containers/array/element_access/constexpr_c++17.cc
index 56d1cf256be..dd69645833f 100644
--- a/libstdc++-v3/testsuite/23_containers/array/element_access/constexpr_c++17.cc
+++ b/libstdc++-v3/testsuite/23_containers/array/element_access/constexpr_c++17.cc
@@ -24,8 +24,6 @@
# error "Feature test macro for array constexpr is missing in <array>"
#elif __cpp_lib_array_constexpr < 201603L
# error "Feature test macro for array constexpr has wrong value in <array>"
-#elif __cpp_lib_array_constexpr > 201603L && __cplusplus == 201703
-# error "Feature test macro for array constexpr has wrong value for C++17"
#endif
constexpr std::size_t test01()
diff --git a/libstdc++-v3/testsuite/23_containers/array/requirements/constexpr_iter.cc b/libstdc++-v3/testsuite/23_containers/array/requirements/constexpr_iter.cc
index a119937f773..566388405b6 100644
--- a/libstdc++-v3/testsuite/23_containers/array/requirements/constexpr_iter.cc
+++ b/libstdc++-v3/testsuite/23_containers/array/requirements/constexpr_iter.cc
@@ -22,12 +22,13 @@
#ifndef __cpp_lib_array_constexpr
# error "Feature test macro for array constexpr is missing in <array>"
-#elif __cpp_lib_array_constexpr < 201603L
+#elif __cpp_lib_array_constexpr < 201803L
# error "Feature test macro for array constexpr has wrong value in <array>"
-#elif __cpp_lib_array_constexpr > 201603L && __cplusplus == 201703
-# error "Feature test macro for array constexpr has wrong value for C++17"
#endif
+// This test is compiled as C++17 because array::iterator is just a pointer,
+// so always meets the C++20 constexpr iterator requirements, even in C++17.
+
constexpr int
test()
{
next prev parent reply other threads:[~2020-04-23 20:44 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-22 21:57 [committed 0/8] libstdc++: Add/update/fix feature test macros Jonathan Wakely
2020-04-22 21:58 ` [committed 1/8] libstdc++: Update value of __cpp_lib_jthread macro Jonathan Wakely
2020-04-22 21:58 ` [committed 2/8] libstdc++: Remove non-standard feature test macros Jonathan Wakely
2020-04-22 21:58 ` [committed 3/8] libstdc++: Add missing " Jonathan Wakely
2020-04-22 21:58 ` [committed 4/8] libstdc++: Rename __cpp_lib_constexpr_invoke macro Jonathan Wakely
2020-04-22 21:59 ` [committed 5/8] libstdc++: Update __cpp_lib_concepts value Jonathan Wakely
2020-04-22 21:59 ` [committed 6/8] libstdc++: Do not define __cpp_lib_constexpr_algorithms in <utility> Jonathan Wakely
2020-04-22 21:59 ` [committed 7/8] libstdc++: Update (and revert) value of __cpp_lib_array_constexpr Jonathan Wakely
2020-04-23 20:44 ` Jonathan Wakely [this message]
2020-04-22 21:59 ` [committed 8/8] libstdc++: Define __cpp_lib_execution feature test macro Jonathan Wakely
2020-04-23 20:41 ` [committed 9/8] libstdc++: Define __cpp_lib_three_way_comparison for freestanding Jonathan Wakely
2020-04-23 20:46 ` [committed 0/8] libstdc++: Add/update/fix feature test macros Jonathan Wakely
2020-04-28 22:52 ` [committed 10/8] libstdc++: Fixes for feature test macros (PR 91480) Jonathan Wakely
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