gcc/libstdc++-v3
Jonathan Wakely ead408529d libstdc++: Fix conditions for optimizing uninitialized algos [PR102064]
While laying some groundwork for constexpr std::vector, I noticed some
bugs in the std::uninitialized_xxx algorithms. The conditions being
checked for optimizing trivial cases were not quite right, as shown in
the examples in the PR.

This consolidates the checks into a single macro. The macro has
appropriate definitions for C++98 or for later standards, to avoid a #if
everywhere the checks are used. For C++11 and later the check makes a
call to a new function doing a static_assert to ensure we don't use
assignment in cases where construction would have been invalid.
Extracting that check to a separate function will be useful for
constexpr std::vector, as that can't use std::uninitialized_copy
directly because it isn't constexpr).

The consolidated checks mean that some slight variations in static
assert message are gone, as there is only one place that does the assert
now. That required adjusting some tests. As part of that the redundant
89164_c++17.cc test was merged into 89164.cc which is compiled as C++17
by default now, but can also use other -std options if the
C++17-specific error is made conditional with a target selector.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>

libstdc++-v3/ChangeLog:

	PR libstdc++/102064
	* include/bits/stl_uninitialized.h (_GLIBCXX_USE_ASSIGN_FOR_INIT):
	Define macro to check conditions for optimizing trivial cases.
	(__check_constructible): New function to do static assert.
	(uninitialized_copy, uninitialized_fill, uninitialized_fill_n):
	Use new macro.
	* testsuite/20_util/specialized_algorithms/uninitialized_copy/1.cc:
	Adjust dg-error pattern.
	* testsuite/23_containers/vector/cons/89164.cc: Likewise. Add
	C++17-specific checks from 89164_c++17.cc.
	* testsuite/23_containers/vector/cons/89164_c++17.cc: Removed.
	* testsuite/20_util/specialized_algorithms/uninitialized_copy/102064.cc:
	New test.
	* testsuite/20_util/specialized_algorithms/uninitialized_copy_n/102064.cc:
	New test.
	* testsuite/20_util/specialized_algorithms/uninitialized_fill/102064.cc:
	New test.
	* testsuite/20_util/specialized_algorithms/uninitialized_fill_n/102064.cc:
	New test.
2021-08-25 22:28:47 +01:00
..
config aix: Protect AIX math.h overloads with new macro. 2021-07-22 11:30:34 -04:00
doc libstdc++: Update C++20 status table for layout-compatibility traits 2021-08-24 16:15:48 +01:00
include libstdc++: Fix conditions for optimizing uninitialized algos [PR102064] 2021-08-25 22:28:47 +01:00
libsupc++ libstdc++: Use __builtin_expect in __dynamic_cast 2021-08-23 14:45:00 +01:00
po
python libstdc++: Fix vector<bool> printer tests to work in debug mode 2021-08-18 14:26:38 +01:00
scripts
src libstdc++: Fix mismatched class-key tags 2021-08-24 14:42:24 +01:00
testsuite libstdc++: Fix conditions for optimizing uninitialized algos [PR102064] 2021-08-25 22:28:47 +01:00
acinclude.m4
aclocal.m4
ChangeLog Daily bump. 2021-08-25 00:16:57 +00:00
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config.h.in libstdc++: Use secure_getenv for filesystem::temp_directory_path() [PR65018] 2021-07-30 18:12:39 +01:00
configure libstdc++: Use secure_getenv for filesystem::temp_directory_path() [PR65018] 2021-07-30 18:12:39 +01:00
configure.ac libstdc++: Use secure_getenv for filesystem::temp_directory_path() [PR65018] 2021-07-30 18:12:39 +01:00
configure.host
crossconfig.m4
fragment.am
linkage.m4
Makefile.am
Makefile.in
README

file: libstdc++-v3/README

New users may wish to point their web browsers to the file
index.html in the 'doc/html' subdirectory.  It contains brief
building instructions and notes on how to configure the library in
interesting ways.