analyzer: fix issues with phi handling
The analyzer's state purging code was overzealously purging state
for ssa names that might be used within phi nodes, leading to
false positives from -Wanalyzer-use-of-uninitialized-value.
This patch updates phi handling in the analyzer to fix these issues.
* region-model.cc (region_model::handle_phi): Add "old_state"
param and use it.
(region_model::update_for_phis): Update so that all of the phi
stmts are effectively handled simultaneously, rather than in
* region-model.h (region_model::handle_phi): Add "old_state"
* state-purge.cc (self_referential_phi_p): Replace with...
(name_used_by_phis_p): ...this new function.
(state_purge_per_ssa_name::process_point): Update to use the
above, so that all phi stmts at a basic block are effectively
considered simultaneously, and only consider the phi arguments for
the pertinent in-edge.
* supergraph.cc (cfg_superedge::get_phi_arg_idx): New.
(cfg_superedge::get_phi_arg): Use the above.
* supergraph.h (cfg_superedge::get_phi_arg_idx): New decl.
* gcc.dg/analyzer/explode-2.c: Remove xfail.
* gcc.dg/analyzer/explode-2a.c: Remove expected leak warning on
* gcc.dg/analyzer/phi-2.c: New test.
Signed-off-by: David Malcolm <email@example.com>
8 files changed