https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107828
Bug ID: 107828 Summary: tree-inlining would generate SSA with incorrect def stmt Product: gcc Version: unknown Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: fxue at os dot amperecomputing.com Target Milestone: --- In the function "remap_gimple_op_r" of tree-inlining.cc: ... if (TREE_CODE (*tp) == SSA_NAME) { *tp = remap_ssa_name (*tp, id); *walk_subtrees = 0; if (is_lhs) SSA_NAME_DEF_STMT (*tp) = wi_p->stmt; return NULL; } The definition statement of original "*tp" may be same as wi_p->stmt. So, we will end up with a statement that it is pointed by both old and new SSA name, while the old one should have been reclaimed. And this happens when some parameter needs to be adjusted during inline versioning as: remap_gimple_stmt() { ... if (id->param_body_adjs) { ... if (!gimple_seq_empty_p (extra_stmts)) { memset (&wi, 0, sizeof (wi)); wi.info = id; for (gimple_stmt_iterator egsi = gsi_start (extra_stmts); !gsi_end_p (egsi); gsi_next (&egsi)) walk_gimple_op (gsi_stmt (egsi), remap_gimple_op_r, &wi); ^^^^^^^^^^^^^^^^^ ... } } ... }