https://gcc.gnu.org/bugzilla/show_bug.cgi?id=19661
--- Comment #20 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The trunk branch has been updated by Andrew Pinski <pins...@gcc.gnu.org>: https://gcc.gnu.org/g:c9dd853680b12d9c9def5de61abde5d057c526ba commit r15-308-gc9dd853680b12d9c9def5de61abde5d057c526ba Author: Andrew Pinski <quic_apin...@quicinc.com> Date: Fri Mar 15 16:34:22 2024 -0700 DCE __cxa_atexit calls where the function is pure/const [PR19661] In C++ sometimes you have a deconstructor function which is "empty", like for an example with unions or with arrays. The front-end might not know it is empty either so this should be done on during optimization.o To implement it I added it to DCE where we mark if a statement is necessary or not. Bootstrapped and tested on x86_64-linux-gnu with no regressions. Changes since v1: * v2: Add support for __aeabi_atexit for arm-*eabi. Add extra comments. Add cxa_atexit-5.C testcase for -fPIC case. * v3: Fix testcases for the __aeabi_atexit (forgot to do in the v2). PR tree-optimization/19661 gcc/ChangeLog: * tree-ssa-dce.cc (is_cxa_atexit): New function. (is_removable_cxa_atexit_call): New function. (mark_stmt_if_obviously_necessary): Don't mark removable cxa_at_exit calls. (mark_all_reaching_defs_necessary_1): Likewise. (propagate_necessity): Likewise. gcc/testsuite/ChangeLog: * g++.dg/tree-ssa/cxa_atexit-1.C: New test. * g++.dg/tree-ssa/cxa_atexit-2.C: New test. * g++.dg/tree-ssa/cxa_atexit-3.C: New test. * g++.dg/tree-ssa/cxa_atexit-4.C: New test. * g++.dg/tree-ssa/cxa_atexit-5.C: New test. * g++.dg/tree-ssa/cxa_atexit-6.C: New test. Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
