https://gcc.gnu.org/bugzilla/show_bug.cgi?id=128365
Bug ID: 128365
Summary: gimple-predicate-analysis.cc: simplify_2 leaks b_chain
on ordered_remove
Product: gcc
Version: 17.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: yansendao at 126 dot com
Target Milestone: ---
predicate::simplify_2 in gcc/gimple-predicate-analysis.cc, when it finds
two equal chains that differ in exactly one negated predicate, removes
the negated predicate from a_chain and drops b_chain from m_preds:
a_chain.ordered_remove (neg_idx);
m_preds.ordered_remove (j);
b_chain (m_preds[j]) is a pred_chain, i.e. vec<pred_info, va_heap, vl_ptr>,
whose storage is heap-allocated. m_preds.ordered_remove (j) drops the
element without releasing that storage, so every hit of this
simplification leaks the b_chain allocation. simplify_2 runs during the
-Wuninitialized / -Wmaybe-uninitialized analysis, so the leak fires on
essentially every compile that reaches it.
Trivial fix: release the chain before removing it.
a_chain.ordered_remove (neg_idx);
b_chain.release ();
m_preds.ordered_remove (j);
Pre-existing and unrelated to PR128102; spotted by Sashiko (VF3) while
reviewing that PR's series.
