My upcoming work replacing the VRP threaders with a fully resolving
backward threader has tripped over various corner cases in the path
sensitive relation oracle. This patch kills second order relations when
we kill a relation.
Tested on x86-64 and ppc64le Linux.
Co-authored-by: Andrew MacLeod <amacl...@redhat.com>
gcc/ChangeLog:
* value-relation.cc (path_oracle::killing_def): Kill second
order relations.
---
gcc/value-relation.cc | 21 ++++++++++++++++++++-
1 file changed, 20 insertions(+), 1 deletion(-)
diff --git a/gcc/value-relation.cc b/gcc/value-relation.cc
index 2acf375ca9a..0ad4f7a9495 100644
--- a/gcc/value-relation.cc
+++ b/gcc/value-relation.cc
@@ -1297,8 +1297,9 @@ path_oracle::killing_def (tree ssa)
fprintf (dump_file, "\n");
}
+ unsigned v = SSA_NAME_VERSION (ssa);
bitmap b = BITMAP_ALLOC (&m_bitmaps);
- bitmap_set_bit (b, SSA_NAME_VERSION (ssa));
+ bitmap_set_bit (b, v);
equiv_chain *ptr = (equiv_chain *) obstack_alloc (&m_chain_obstack,
sizeof (equiv_chain));
ptr->m_names = b;
@@ -1306,6 +1307,24 @@ path_oracle::killing_def (tree ssa)
ptr->m_next = m_equiv.m_next;
m_equiv.m_next = ptr;
bitmap_ior_into (m_equiv.m_names, b);
+
+ // Walk the relation list an remove SSA from any relations.
+ if (!bitmap_bit_p (m_relations.m_names, v))
+ return;
+
+ bitmap_clear_bit (m_relations.m_names, v);
+ relation_chain **prev = &(m_relations.m_head);
+ relation_chain *next = NULL;
+ for (relation_chain *ptr = m_relations.m_head; ptr; ptr = next)
+ {
+ gcc_checking_assert (*prev == ptr);
+ next = ptr->m_next;
+ if (SSA_NAME_VERSION (ptr->op1 ()) == v
+ || SSA_NAME_VERSION (ptr->op2 ()) == v)
+ *prev = ptr->m_next;
+ else
+ prev = &(ptr->m_next);
+ }
}
// Register relation K between SSA1 and SSA2, resolving unknowns by
--
2.31.1
