only create Psi if allowed by backend

[r8354]

diff --git a/ir/opt/ifconv.c b/ir/opt/ifconv.c
index 07d2dcd..8be31fb 100644 (file)
--- a/ir/opt/ifconv.c
+++ b/ir/opt/ifconv.c
@@ -42,6 +42,18 @@
 
 DEBUG_ONLY(firm_dbg_module_t *dbg);
 
+/** allow every Psi to be created. */
+static int default_allow_mux(ir_node *sel, ir_node *false_res, ir_node *true_res) {
+       return 1;
+}
+
+/**
+ * Default options.
+ */
+static const opt_if_conv_info_t default_info = {
+       0,    /* doesn't matter for Psi */
+       default_allow_mux
+};
 
 /**
  * Additional block info.
@@ -238,6 +250,7 @@ static void if_conv_walker(ir_node* block, void* env)
 {
        int arity;
        int i;
+       opt_if_conv_info_t *opt_info = env;
 
        /* Bail out, if there are no Phis at all */
        if (get_block_blockinfo(block)->phi == NULL) return;
@@ -259,14 +272,16 @@ restart:
 
                        cond = get_Proj_pred(projx0);
                        if (get_irn_op(cond) != op_Cond) continue;
+
                        /* We only handle boolean decisions, no switches */
                        if (get_irn_mode(get_Cond_selector(cond)) != mode_b) continue;
+                       if (! opt_info->allow_mux(get_Cond_selector(cond), NULL, NULL)) continue;
 
                        for (j = i + 1; j < arity; ++j) {
                                ir_node* projx1;
                                ir_node* conds[1];
                                ir_node* vals[2];
-                               ir_node* psi;
+                               ir_node* psi = NULL;
                                ir_node* psi_block;
                                ir_node* phi;
 
@@ -309,12 +324,14 @@ restart:
                                                        vals[0] = val_j;
                                                        vals[1] = val_i;
                                                }
+
                                                psi = new_r_Psi(
                                                        current_ir_graph, psi_block, 1, conds, vals, get_irn_mode(phi)
                                                );
                                                DB((dbg, LEVEL_2, "Generating %+F for %+F\n", psi, phi));
                                        }
 
+                                       /* only exchange if we have a Psi */
                                        if (arity == 2) {
                                                exchange(phi, psi);
                                        } else {
@@ -604,10 +621,17 @@ static void optimise_psis(ir_node* node, void* env)
 void opt_if_conv(ir_graph *irg, const opt_if_conv_info_t *params)
 {
        struct obstack obst;
+       opt_if_conv_info_t p;
 
-       if (!get_opt_if_conversion())
+       if (! get_opt_if_conversion())
                return;
 
+       /* get the parameters */
+       if (params)
+               memcpy(&p, params, sizeof(p));
+       else
+               memcpy(&p, &default_info, sizeof(p));
+
        FIRM_DBG_REGISTER(dbg, "firm.opt.ifconv");
 
        DB((dbg, LEVEL_1, "Running if-conversion on %+F\n", irg));
@@ -621,7 +645,7 @@ void opt_if_conv(ir_graph *irg, const opt_if_conv_info_t *params)
        obstack_init(&obst);
        irg_block_walk_graph(irg, init_block_link, NULL, &obst);
        irg_walk_graph(irg, collect_phis, NULL, NULL);
-       irg_block_walk_graph(irg, NULL, if_conv_walker, NULL);
+       irg_block_walk_graph(irg, NULL, if_conv_walker, &p);
 
        local_optimize_graph(irg);