On 5/2/24 3:56 PM, Andrew Pinski wrote:
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. 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.
OK jeff