https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107637
--- Comment #4 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:650e91566561870f3d1c8d5b92e6613296ee1a8d commit r15-3840-g650e91566561870f3d1c8d5b92e6613296ee1a8d Author: Jakub Jelinek <ja...@redhat.com> Date: Tue Sep 24 20:19:50 2024 +0200 c++: Implement C++23 P2718R0 - Wording for P2644R1 Fix for Range-based for Loop [PR107637] The following patch implements the C++23 P2718R0 paper - Wording for P2644R1 Fix for Range-based for Loop. The patch introduces a new option, -f{,no-}range-for-ext-temps so that user can control the behavior even in older C++ versions. The option is on by default in C++23 and later (-fno-range-for-ext-temps is an error in that case) and in the -std=gnu++11 ... -std=gnu++20 modes (one can use -fno-range-for-ext-temps to request previous behavior in that case), and is not enabled by default in -std=c++11 ... -std=c++20 modes but one can explicitly enable it with -frange-for-ext-temps. As all the temporaries from __for_range initialization should have life extended until the end of __for_range scope, this patch disables (for -frange-for-ext-temps and if !processing_template_decl) CLEANUP_POINT_EXPR wrapping of the __for_range declaration, also disables -Wdangling-reference warning as well as the rest of extend_ref_init_temps (we know the __for_range temporary is not TREE_STATIC and as all the temporaries from the initializer will be life extended, we shouldn't try to handle temporaries referenced by references any differently) and adds an extra push_stmt_list/pop_stmt_list before cp_finish_decl of __for_range and after end of the for body and wraps all that into CLEANUP_POINT_EXPR. I had to repeat that also for OpenMP range loops because those are handled differently. 2024-09-24 Jakub Jelinek <ja...@redhat.com> PR c++/107637 gcc/ * omp-general.cc (find_combined_omp_for, find_nested_loop_xform): Handle CLEANUP_POINT_EXPR like TRY_FINALLY_EXPR. * doc/invoke.texi (frange-for-ext-temps): Document. Add -fconcepts to the C++ option list. gcc/c-family/ * c.opt (frange-for-ext-temps): New option. * c-opts.cc (c_common_post_options): Set flag_range_for_ext_temps for C++23 or later or for C++11 or later in !flag_iso mode if the option wasn't set by user. * c-cppbuiltin.cc (c_cpp_builtins): Change __cpp_range_based_for value for flag_range_for_ext_temps from 201603L to 202212L in C++17 or later. * c-omp.cc (c_find_nested_loop_xform_r): Handle CLEANUP_POINT_EXPR like TRY_FINALLY_EXPR. gcc/cp/ * cp-tree.h: Implement C++23 P2718R0 - Wording for P2644R1 Fix for Range-based for Loop. (cp_convert_omp_range_for): Add bool tmpl_p argument. (find_range_for_decls): Declare. * parser.cc (cp_convert_range_for): For flag_range_for_ext_temps call push_stmt_list () before cp_finish_decl for range_temp and save it temporarily to FOR_INIT_STMT. (cp_convert_omp_range_for): Add tmpl_p argument. If set, remember DECL_NAME of range_temp and for cp_finish_decl call restore it before clearing it again, if unset, don't adjust DECL_NAME of range_temp at all. (cp_parser_omp_loop_nest): For flag_range_for_ext_temps range for add CLEANUP_POINT_EXPR around sl. Call find_range_for_decls and adjust DECL_NAMEs for range fors if not processing_template_decl. Adjust cp_convert_omp_range_for caller. Remove superfluous backslash at the end of line. * decl.cc (initialize_local_var): For flag_range_for_ext_temps temporarily clear stmts_are_full_exprs_p rather than set for for_range__identifier decls. * call.cc (extend_ref_init_temps): For flag_range_for_ext_temps return init early for for_range__identifier decls. * semantics.cc (find_range_for_decls): New function. (finish_for_stmt): Use it. For flag_range_for_ext_temps if cp_convert_range_for set FOR_INIT_STMT, pop_stmt_list it and wrap into CLEANUP_POINT_EXPR. * pt.cc (tsubst_omp_for_iterator): Adjust tsubst_omp_for_iterator caller. (tsubst_stmt) <case OMP_FOR>: For flag_range_for_ext_temps if there are any range fors in the loop nest, add push_stmt_list starting before the initializations, pop_stmt_list it after the body and wrap into CLEANUP_POINT_EXPR. Change DECL_NAME of range for temps from NULL to for_range_identifier. gcc/testsuite/ * g++.dg/cpp23/range-for1.C: New test. * g++.dg/cpp23/range-for2.C: New test. * g++.dg/cpp23/range-for3.C: New test. * g++.dg/cpp23/range-for4.C: New test. * g++.dg/cpp23/range-for5.C: New test. * g++.dg/cpp23/range-for6.C: New test. * g++.dg/cpp23/range-for7.C: New test. * g++.dg/cpp23/range-for8.C: New test. * g++.dg/cpp23/feat-cxx2b.C (__cpp_range_based_for): Check for 202212L rather than 201603L. * g++.dg/cpp26/feat-cxx26.C (__cpp_range_based_for): Likewise. * g++.dg/warn/Wdangling-reference4.C: Don't expect warning for C++23 or newer. Use dg-additional-options rather than dg-options. libgomp/ * testsuite/libgomp.c++/range-for-1.C: New test. * testsuite/libgomp.c++/range-for-2.C: New test. * testsuite/libgomp.c++/range-for-3.C: New test. * testsuite/libgomp.c++/range-for-4.C: New test. * testsuite/libgomp.c++/range-for-5.C: New test.
