- better solution for the "mode_M node computes Top" problem

[r23152]

diff --git a/ir/opt/combo.c b/ir/opt/combo.c
index 7e940d3..a665656 100644 (file)
--- a/ir/opt/combo.c
+++ b/ir/opt/combo.c
@@ -686,12 +686,6 @@ static inline lattice_elem_t get_partition_type(const partition_t *X) {
 static node_t *create_partition_node(ir_node *irn, partition_t *part, environment_t *env) {
        /* create a partition node and place it in the partition */
        node_t *node = obstack_alloc(&env->obst, sizeof(*node));
-       tarval *init = tarval_top;
-
-       if (is_Proj(irn) && get_irn_mode(irn) == mode_M) {
-               /* mode_M Proj's must never be removed */
-               init = tarval_bottom;
-       }
 
        INIT_LIST_HEAD(&node->node_list);
        INIT_LIST_HEAD(&node->cprop_list);
@@ -699,7 +693,7 @@ static node_t *create_partition_node(ir_node *irn, partition_t *part, environmen
        node->part           = part;
        node->next           = NULL;
        node->race_next      = NULL;
-       node->type.tv        = init;
+       node->type.tv        = tarval_top;
        node->max_user_input = 0;
        node->next_edge      = 0;
        node->n_followers    = 0;
@@ -2525,14 +2519,16 @@ static void compute(node_t *node) {
        ir_node *irn = node->node;
        compute_func func;
 
+#ifndef VERIFY_MONOTONE
        /*
         * Once a node reaches bottom, the type cannot fall further
         * in the lattice and we can stop computation.
-        * This reduces further checking for ProjM not allowed to raise
-        * its type below...
+        * Do not take this exit if the monotony verifier is
+        * enabled to catch errors.
         */
        if (node->type.tv == tarval_bottom)
                return;
+#endif
 
        if (is_no_Block(irn)) {
                /* for pinned nodes, check its control input */
@@ -3240,7 +3236,6 @@ static void apply_result(ir_node *irn, void *ctx) {
                /* blocks already handled, do not touch the End node */
        } else {
                node_t  *block = get_irn_node(get_nodes_block(irn));
-               ir_mode *mode = get_irn_mode(irn);
 
                if (block->type.tv == tarval_unreachable) {
                        ir_node *bad = get_irg_bad(current_ir_graph);
@@ -3252,20 +3247,26 @@ static void apply_result(ir_node *irn, void *ctx) {
                        DB((dbg, LEVEL_1, "%+F is unreachable\n", irn));
                        exchange(irn, bad);
                        env->modified = 1;
-               } else if (mode == mode_M && is_Proj(irn)) {
-                       ir_node *pred  = get_Proj_pred(irn);
-                       node_t  *pnode = get_irn_node(pred);
-
-                       if (pnode->type.tv == tarval_top) {
-                               /* skip the predecessor */
-                               ir_node *mem = get_memop_mem(pred);
-                               node->node = mem;
-                               DB((dbg, LEVEL_1, "%+F computes Top, replaced by %+F\n", irn, mem));
-                               exchange(irn, mem);
-                               env->modified = 1;
-                       }
                } else if (node->type.tv == tarval_top) {
-                       if (mode == mode_T) {
+                       ir_mode *mode = get_irn_mode(irn);
+
+                       if (mode == mode_M) {
+                               /* never kill a mode_M node */
+                               if (is_Proj(irn)) {
+                                       ir_node *pred  = get_Proj_pred(irn);
+                                       node_t  *pnode = get_irn_node(pred);
+
+                                       if (pnode->type.tv == tarval_top) {
+                                               /* skip the predecessor */
+                                               ir_node *mem = get_memop_mem(pred);
+                                               node->node = mem;
+                                               DB((dbg, LEVEL_1, "%+F computes Top, replaced by %+F\n", irn, mem));
+                                               exchange(irn, mem);
+                                               env->modified = 1;
+                                       }
+                               }
+                               /* leave other nodes, especially PhiM */
+                       } else if (mode == mode_T) {
                                /* Do not kill mode_T nodes, kill their Projs */
                        } else if (! is_Unknown(irn)) {
                                /* don't kick away Unknown's, they might be still needed */