Add -Wuse-after-free [PR80532].

gcc/c-family/ChangeLog

	PR tree-optimization/80532
	* c.opt (-Wuse-after-free): New options.

gcc/ChangeLog:

	PR tree-optimization/80532
	* common.opt (-Wuse-after-free): New options.
	* diagnostic-spec.c (nowarn_spec_t::nowarn_spec_t): Handle
	OPT_Wreturn_local_addr and OPT_Wuse_after_free_.
	* diagnostic-spec.h (NW_DANGLING): New enumerator.
	* doc/invoke.texi (-Wuse-after-free): Document new option.
	* gimple-ssa-warn-access.cc (pass_waccess::check_call): Rename...
	(pass_waccess::check_call_access): ...to this.
	(pass_waccess::check): Rename...
	(pass_waccess::check_block): ...to this.
	(pass_waccess::check_pointer_uses): New function.
	(pass_waccess::gimple_call_return_arg): New function.
	(pass_waccess::warn_invalid_pointer): New function.
	(pass_waccess::check_builtin): Handle free and realloc.
	(gimple_use_after_inval_p): New function.
	(get_realloc_lhs): New function.
	(maybe_warn_mismatched_realloc): New function.
	(pointers_related_p): New function.
	(pass_waccess::check_call): Call check_pointer_uses.
	(pass_waccess::execute): Compute and free dominance info.

libcpp/ChangeLog:

	* files.c (_cpp_find_file): Substitute a valid pointer for
	an invalid one to avoid -Wuse-after-free.

libiberty/ChangeLog:

	* regex.c: Suppress -Wuse-after-free.

gcc/testsuite/ChangeLog:

	PR tree-optimization/80532
	* gcc.dg/Wmismatched-dealloc-2.c: Avoid -Wuse-after-free.
	* gcc.dg/Wmismatched-dealloc-3.c: Same.
	* gcc.dg/analyzer/file-1.c: Prune expected warning.
	* gcc.dg/analyzer/file-2.c: Same.
	* gcc.dg/attr-alloc_size-6.c: Disable -Wuse-after-free.
	* gcc.dg/attr-alloc_size-7.c: Same.
	* c-c++-common/Wuse-after-free-2.c: New test.
	* c-c++-common/Wuse-after-free-3.c: New test.
	* c-c++-common/Wuse-after-free-4.c: New test.
	* c-c++-common/Wuse-after-free-5.c: New test.
	* c-c++-common/Wuse-after-free-6.c: New test.
	* c-c++-common/Wuse-after-free-7.c: New test.
	* c-c++-common/Wuse-after-free.c: New test.
	* g++.dg/warn/Wmismatched-dealloc-3.C: New test.
	* g++.dg/warn/Wuse-after-free.C: New test.