https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105838
--- Comment #17 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jason Merrill <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:1e1847612d7f169f82c985b0b3a5e3301d6fe999 commit r13-4563-g1e1847612d7f169f82c985b0b3a5e3301d6fe999 Author: Jason Merrill <ja...@redhat.com> Date: Mon Dec 5 15:19:27 2022 -0500 c++: fewer allocator temps [PR105838] In this PR, initializing the array of std::string to pass to the vector initializer_list constructor gets very confusing to the optimizers as the number of elements increases, primarily because of all the std::allocator temporaries passed to all the string constructors. Instead of creating one for each string, let's share an allocator between all the strings; we can do this safely because we know that std::allocator is stateless and that string doesn't care about the object identity of its allocator parameter. PR c++/105838 gcc/cp/ChangeLog: * cp-tree.h (is_std_allocator): Declare. * constexpr.cc (is_std_allocator): Split out from... (is_std_allocator_allocate): ...here. * init.cc (find_temps_r): New. (find_allocator_temp): New. (build_vec_init): Use it. gcc/testsuite/ChangeLog: * g++.dg/tree-ssa/allocator-opt1.C: New test.
