count executed optimization

[libfirm] / ir / lower / lower_mode_b.c

diff --git a/ir/lower/lower_mode_b.c b/ir/lower/lower_mode_b.c
index 9d42f7c..2e95088 100644 (file)
--- a/ir/lower/lower_mode_b.c
+++ b/ir/lower/lower_mode_b.c
@@ -32,13 +32,41 @@
 #include "ircons_t.h"
 #include "irgwalk.h"
 #include "irtools.h"
+#include "iredges.h"
 #include "tv.h"
 #include "error.h"
 #include "lowering.h"
+#include "pdeq.h"
 
 static ir_mode *lowered_mode     = NULL;
 static int      lower_direct_cmp = 0;
 static ir_type *lowered_type     = NULL;
+static pdeq    *lowered_nodes    = NULL;
+
+/**
+ * Removes a node if its out-edge count has reached 0.
+ * temporary hack until we have proper automatic dead code elimination.
+ */
+static void maybe_kill_node(ir_node *node)
+{
+       ir_graph *irg;
+       int       i, arity;
+
+       if(get_irn_n_edges(node) != 0)
+               return;
+
+       irg = get_irn_irg(node);
+
+       assert(!is_Bad(node));
+
+       arity = get_irn_arity(node);
+       for (i = 0; i < arity; ++i) {
+               set_irn_n(node, i, new_Bad());
+       }
+       set_nodes_block(node, new_Bad());
+
+       edges_node_deleted(node, irg);
+}
 
 static ir_node *create_not(dbg_info *dbgi, ir_node *node)
 {
@@ -120,6 +148,7 @@ static ir_node *lower_node(ir_node *node)
                new_phi = new_rd_Phi(dbgi, irg, block, arity, in,
                                              lowered_mode);
                set_irn_link(node, new_phi);
+               pdeq_putr(lowered_nodes, node);
 
                for(i = 0; i < arity; ++i) {
                        ir_node *in     = get_irn_n(node, i);
@@ -145,6 +174,7 @@ static ir_node *lower_node(ir_node *node)
                set_irn_mode(copy, lowered_mode);
 
                set_irn_link(node, copy);
+               pdeq_putr(lowered_nodes, node);
                return copy;
        }
        if(op == op_Not) {
@@ -153,6 +183,7 @@ static ir_node *lower_node(ir_node *node)
 
                res = create_not(dbgi, low_op);
                set_irn_link(node, res);
+               pdeq_putr(lowered_nodes, node);
                return res;
        }
        if(op == op_Psi) {
@@ -175,6 +206,7 @@ static ir_node *lower_node(ir_node *node)
                                              lowered_mode);
 
                set_irn_link(node, or);
+               pdeq_putr(lowered_nodes, node);
                return or;
        }
        if(op == op_Conv) {
@@ -195,6 +227,7 @@ static ir_node *lower_node(ir_node *node)
                                               lowered_mode);
 
                set_irn_link(node, psi);
+               pdeq_putr(lowered_nodes, node);
                return psi;
        }
        if(op == op_Proj) {
@@ -207,7 +240,7 @@ static ir_node *lower_node(ir_node *node)
 
                        if ((mode_is_int(mode) || mode_is_reference(mode)) && (
                                                get_mode_size_bits(mode) < get_mode_size_bits(lowered_mode) ||
-                                               (is_Const(right) && is_Const_null(right))
+                                               (mode_is_signed(mode) && is_Const(right) && is_Const_null(right))
                                        )) {
                                int      pnc      = get_Proj_proj(node);
                                int      need_not = 0;
@@ -219,7 +252,7 @@ static ir_node *lower_node(ir_node *node)
                                        a = left;
                                        b = right;
                                } else if(pnc == pn_Cmp_Le) {
-                                       /* a <= b  -> ((a - b) >> 31) ^ 1 */
+                                       /* a <= b  -> ~(a - b) >> 31 */
                                        a        = right;
                                        b        = left;
                                        need_not = 1;
@@ -228,14 +261,14 @@ static ir_node *lower_node(ir_node *node)
                                        a = right;
                                        b = left;
                                } else if(pnc == pn_Cmp_Ge) {
-                                       /* a >= b   -> ((a - b) >> 31) ^ 1 */
+                                       /* a >= b   -> ~(a - b) >> 31 */
                                        a        = left;
                                        b        = right;
                                        need_not = 1;
                                }
 
                                if(a != NULL) {
-                                       tarval  *tv        = new_tarval_from_long(31, mode_Iu);
+                                       tarval  *tv        = new_tarval_from_long(get_mode_size_bits(lowered_mode) - 1, mode_Iu);
                                        ir_node *shift_cnt = new_d_Const(dbgi, mode_Iu, tv);
 
                                        if(mode != lowered_mode) {
@@ -244,13 +277,14 @@ static ir_node *lower_node(ir_node *node)
                                        }
 
                                        res = new_rd_Sub(dbgi, irg, block, a, b, lowered_mode);
+                                       if(need_not) {
+                                               res = new_rd_Not(dbgi, irg, block, res, lowered_mode);
+                                       }
                                        res = new_rd_Shr(dbgi, irg, block, res, shift_cnt,
                                                         lowered_mode);
 
-                                       if(need_not) {
-                                               res = create_not(dbgi, res);
-                                       }
                                        set_irn_link(node, res);
+                                       pdeq_putr(lowered_nodes, node);
                                        return res;
                                }
                        }
@@ -267,6 +301,7 @@ static ir_node *lower_node(ir_node *node)
                                                      lowered_mode);
 
                        set_irn_link(node, psi);
+                       pdeq_putr(lowered_nodes, node);
                        return psi;
                        }
                } else if(is_Proj(pred) && is_Call(get_Proj_pred(pred))) {
@@ -296,6 +331,7 @@ static ir_node *lower_node(ir_node *node)
                        panic("invalid boolean const %+F", node);
                }
                set_irn_link(node, res);
+               pdeq_putr(lowered_nodes, node);
                return res;
        }
 
@@ -351,8 +387,17 @@ void ir_lower_mode_b(ir_graph *irg, ir_mode *mode, int do_lower_direct_cmp)
 {
        lowered_mode     = mode;
        lower_direct_cmp = do_lower_direct_cmp;
+       lowered_nodes    = new_pdeq();
        set_using_irn_link(irg);
+
        irg_walk_graph(irg, clear_links, NULL, NULL);
        irg_walk_graph(irg, lower_mode_b_walker, NULL, NULL);
+
+       while(!pdeq_empty(lowered_nodes)) {
+               ir_node *node = (ir_node*) pdeq_getr(lowered_nodes);
+               maybe_kill_node(node);
+       }
+       del_pdeq(lowered_nodes);
+
        clear_using_irn_link(irg);
 }