+/* Helper function for rewrite_stmt. Rewrite uses in a debug stmt. */
+
+static void
+rewrite_debug_stmt_uses (gimple stmt)
+{
+ use_operand_p use_p;
+ ssa_op_iter iter;
+ bool update = false;
+
+ FOR_EACH_SSA_USE_OPERAND (use_p, stmt, iter, SSA_OP_USE)
+ {
+ tree var = USE_FROM_PTR (use_p), def = NULL_TREE;
+ gcc_assert (DECL_P (var));
+ if (var_ann (var) == NULL)
+ {
+ if (TREE_CODE (var) == PARM_DECL && single_succ_p (ENTRY_BLOCK_PTR))
+ {
+ gimple_stmt_iterator gsi
+ = gsi_after_labels (single_succ (ENTRY_BLOCK_PTR));
+ int lim;
+ /* Search a few source bind stmts at the start of first bb to
+ see if a DEBUG_EXPR_DECL can't be reused. */
+ for (lim = 32;
+ !gsi_end_p (gsi) && lim > 0;
+ gsi_next (&gsi), lim--)
+ {
+ gimple gstmt = gsi_stmt (gsi);
+ if (!gimple_debug_source_bind_p (gstmt))
+ break;
+ if (gimple_debug_source_bind_get_value (gstmt) == var)
+ {
+ def = gimple_debug_source_bind_get_var (gstmt);
+ if (TREE_CODE (def) == DEBUG_EXPR_DECL)
+ break;
+ else
+ def = NULL_TREE;
+ }
+ }
+ /* If not, add a new source bind stmt. */
+ if (def == NULL_TREE)
+ {
+ gimple def_temp;
+ def = make_node (DEBUG_EXPR_DECL);
+ def_temp = gimple_build_debug_source_bind (def, var, NULL);
+ DECL_ARTIFICIAL (def) = 1;
+ TREE_TYPE (def) = TREE_TYPE (var);
+ DECL_MODE (def) = DECL_MODE (var);
+ gsi = gsi_after_labels (single_succ (ENTRY_BLOCK_PTR));
+ gsi_insert_before (&gsi, def_temp, GSI_SAME_STMT);
+ }
+ update = true;
+ }
+ }
+ else
+ {
+ def = get_current_def (var);
+ /* Check if get_current_def can be trusted. */
+ if (def)
+ {
+ basic_block bb = gimple_bb (stmt);
+ basic_block def_bb
+ = SSA_NAME_IS_DEFAULT_DEF (def)
+ ? NULL : gimple_bb (SSA_NAME_DEF_STMT (def));
+
+ /* If definition is in current bb, it is fine. */
+ if (bb == def_bb)
+ ;
+ /* If definition bb doesn't dominate the current bb,
+ it can't be used. */
+ else if (def_bb && !dominated_by_p (CDI_DOMINATORS, bb, def_bb))
+ def = NULL;
+ /* If there is just one definition and dominates the current
+ bb, it is fine. */
+ else if (get_phi_state (var) == NEED_PHI_STATE_NO)
+ ;
+ else
+ {
+ struct def_blocks_d *db_p = get_def_blocks_for (var);
+
+ /* If there are some non-debug uses in the current bb,
+ it is fine. */
+ if (bitmap_bit_p (db_p->livein_blocks, bb->index))
+ ;
+ /* Otherwise give up for now. */
+ else
+ def = NULL;
+ }
+ }
+ }
+ if (def == NULL)
+ {
+ gimple_debug_bind_reset_value (stmt);
+ update_stmt (stmt);
+ return;
+ }
+ SET_USE (use_p, def);
+ }
+ if (update)
+ update_stmt (stmt);
+}
+