analyzer: handle NRVO and DECL_BY_REFERENCE [PR111536]

The analyzer was issuing false warnings about uninitialized variables
in C++ in places where NRVO was marking DECL_RESULT with
DECL_BY_REFERENCE.

Fixed thusly.

gcc/analyzer/ChangeLog:
	PR analyzer/111536
	* engine.cc (maybe_update_for_edge): Update for new call_stmt
	param to region_model::push_frame.
	* program-state.cc (program_state::push_frame): Likewise.
	* region-model.cc (region_model::update_for_gcall): Likewise.
	(region_model::push_frame): Add "call_stmt" param.
	Handle DECL_RESULT with DECL_BY_REFERENCE set on it by stashing
	the region of the lhs of the call_stmt in the caller frame,
	and writing a reference to it within the "result" in the callee
	frame.
	(region_model::pop_frame): Don't write back to the LHS for
	DECL_BY_REFERENCE results.
	(selftest::test_stack_frames): Update for new call_stmt param to
	region_model::push_frame.
	(selftest::test_get_representative_path_var): Likewise.
	(selftest::test_state_merging): Likewise.
	(selftest::test_alloca): Likewise.
	* region-model.h (region_model::push_frame): Add "call_stmt"
	param.
	* region.cc: Include "tree-ssa.h".
	(region::can_have_initial_svalue_p): Use ssa_defined_default_def_p
	for ssa names, rather than special-casing it for just parameters.
	This should now also cover DECL_RESULT with DECL_BY_REFERENCE and
	hard registers.
	* sm-signal.cc (update_model_for_signal_handler): Update for new
	call_stmt param to region_model::push_frame.
	* state-purge.cc (state_purge_per_decl::process_worklists):
	Likewise.

gcc/testsuite/ChangeLog:
	PR analyzer/111536
	* c-c++-common/analyzer/hard-reg-1.c: New test.
	* g++.dg/analyzer/nrvo-1.C: New test.
	* g++.dg/analyzer/nrvo-2.C: New test.
	* g++.dg/analyzer/nrvo-pr111536-1.C: New test.
	* g++.dg/analyzer/nrvo-pr111536-1b.C: New test.
	* g++.dg/analyzer/nrvo-pr111536-2.C: New test.
	* g++.dg/analyzer/nrvo-pr111536-2b.C: New test.

Signed-off-by: David Malcolm <dmalcolm@redhat.com>

0 files changed, 0 insertions, 0 deletions