+/* Returns true when P1 and P2 are close phis with the same
+ argument. */
+
+static inline bool
+same_close_phi_node (gimple p1, gimple p2)
+{
+ return operand_equal_p (gimple_phi_arg_def (p1, 0),
+ gimple_phi_arg_def (p2, 0), 0);
+}
+
+/* Remove the close phi node at GSI and replace its rhs with the rhs
+ of PHI. */
+
+static void
+remove_duplicate_close_phi (gimple phi, gimple_stmt_iterator *gsi)
+{
+ gimple use_stmt;
+ use_operand_p use_p;
+ imm_use_iterator imm_iter;
+ tree res = gimple_phi_result (phi);
+ tree def = gimple_phi_result (gsi_stmt (*gsi));
+
+ gcc_assert (same_close_phi_node (phi, gsi_stmt (*gsi)));
+
+ FOR_EACH_IMM_USE_STMT (use_stmt, imm_iter, def)
+ {
+ FOR_EACH_IMM_USE_ON_STMT (use_p, imm_iter)
+ SET_USE (use_p, res);
+
+ update_stmt (use_stmt);
+
+ /* It is possible that we just created a duplicate close-phi
+ for an already-processed containing loop. Check for this
+ case and clean it up. */
+ if (gimple_code (use_stmt) == GIMPLE_PHI
+ && gimple_phi_num_args (use_stmt) == 1)
+ make_close_phi_nodes_unique (gimple_bb (use_stmt));
+ }
+
+ remove_phi_node (gsi, true);
+}
+
+/* Removes all the close phi duplicates from BB. */
+
+static void
+make_close_phi_nodes_unique (basic_block bb)
+{
+ gimple_stmt_iterator psi;
+
+ for (psi = gsi_start_phis (bb); !gsi_end_p (psi); gsi_next (&psi))
+ {
+ gimple_stmt_iterator gsi = psi;
+ gimple phi = gsi_stmt (psi);
+
+ /* At this point, PHI should be a close phi in normal form. */
+ gcc_assert (gimple_phi_num_args (phi) == 1);
+
+ /* Iterate over the next phis and remove duplicates. */
+ gsi_next (&gsi);
+ while (!gsi_end_p (gsi))
+ if (same_close_phi_node (phi, gsi_stmt (gsi)))
+ remove_duplicate_close_phi (phi, &gsi);
+ else
+ gsi_next (&gsi);
+ }
+}
+