fix condeval ssa recondstruction

[libfirm] / ir / opt / condeval.c

diff --git a/ir/opt/condeval.c b/ir/opt/condeval.c
index 7113fd8..d3b29d7 100644 (file)
--- a/ir/opt/condeval.c
+++ b/ir/opt/condeval.c
@@ -69,7 +69,11 @@ static void add_pred(ir_node* node, ir_node* x)
        set_irn_in(node, n + 1, ins);
 }
 
-static ir_node *search_def_and_create_phis(ir_node *block, ir_mode *mode)
+static ir_node *ssa_second_def;
+static ir_node *ssa_second_def_block;
+
+static ir_node *search_def_and_create_phis(ir_node *block, ir_mode *mode,
+                                           int first)
 {
        int i;
        int n_cfgpreds;
@@ -87,6 +91,15 @@ static ir_node *search_def_and_create_phis(ir_node *block, ir_mode *mode)
                return value;
        }
 
+       /* the other defs can't be marked for cases where a user of the original
+        * value is in the same block as the alternative definition.
+        * In this case we mustn't use the alternative definition.
+        * So we keep a flag that indicated wether we walked at least 1 block
+        * away and may use the alternative definition */
+       if (block == ssa_second_def_block && !first) {
+               return ssa_second_def;
+       }
+
        irg = get_irn_irg(block);
        assert(block != get_irg_start_block(irg));
 
@@ -94,7 +107,7 @@ static ir_node *search_def_and_create_phis(ir_node *block, ir_mode *mode)
        n_cfgpreds = get_Block_n_cfgpreds(block);
        if(n_cfgpreds == 1) {
                ir_node *pred_block = get_Block_cfgpred_block(block, 0);
-               ir_node *value      = search_def_and_create_phis(pred_block, mode);
+               ir_node *value      = search_def_and_create_phis(pred_block, mode, 0);
 
                set_irn_link(block, value);
                mark_irn_visited(block);
@@ -113,7 +126,7 @@ static ir_node *search_def_and_create_phis(ir_node *block, ir_mode *mode)
        /* set Phi predecessors */
        for(i = 0; i < n_cfgpreds; ++i) {
                ir_node *pred_block = get_Block_cfgpred_block(block, i);
-               ir_node *pred_val = search_def_and_create_phis(pred_block, mode);
+               ir_node *pred_val   = search_def_and_create_phis(pred_block, mode, 0);
 
                set_irn_n(phi, i, pred_val);
        }
@@ -126,35 +139,26 @@ static ir_node *search_def_and_create_phis(ir_node *block, ir_mode *mode)
  * first value (the users are determined through the out-edges of the value).
  * Uses the irn_visited flags. Works without using the dominance tree.
  */
-static void construct_ssa(ir_node * const *blocks, ir_node * const *vals, int n_vals)
+static void construct_ssa(ir_node *orig_block, ir_node *orig_val,
+                          ir_node *second_block, ir_node *second_val)
 {
-       int i;
        ir_graph *irg;
        ir_mode *mode;
        const ir_edge_t *edge;
        const ir_edge_t *next;
-       ir_node *value;
-
-       assert(n_vals == 2);
 
-       irg = get_irn_irg(vals[0]);
+       irg = get_irn_irg(orig_val);
        inc_irg_visited(irg);
 
-       mode = get_irn_mode(vals[0]);
-       for(i = 0; i < n_vals; ++i) {
-               ir_node *value = vals[i];
-               ir_node *value_block = blocks[i];
+       mode = get_irn_mode(orig_val);
+       set_irn_link(orig_block, orig_val);
+       mark_irn_visited(orig_block);
 
-               assert(get_irn_mode(value) == mode || is_Bad(value));
-
-               set_irn_link(value_block, value);
-               mark_irn_visited(value_block);
-       }
+       ssa_second_def_block = second_block;
+       ssa_second_def       = second_val;
 
        /* Only fix the users of the first, i.e. the original node */
-       value = vals[0];
-
-       foreach_out_edge_safe(value, edge, next) {
+       foreach_out_edge_safe(orig_val, edge, next) {
                ir_node *user = get_edge_src_irn(edge);
                int j = get_edge_src_pos(edge);
                ir_node *user_block = get_nodes_block(user);
@@ -164,16 +168,13 @@ static void construct_ssa(ir_node * const *blocks, ir_node * const *vals, int n_
                if (is_End(user))
                        continue;
 
-               if (user_block == blocks[1])
-                       continue;
-
                DB((dbg, LEVEL_3, ">>> Fixing user %+F (pred %d == %+F)\n", user, j, get_irn_n(user, j)));
 
                if(is_Phi(user)) {
                        ir_node *pred_block = get_Block_cfgpred_block(user_block, j);
-                       newval = search_def_and_create_phis(pred_block, mode);
+                       newval = search_def_and_create_phis(pred_block, mode, 1);
                } else {
-                       newval = search_def_and_create_phis(user_block, mode);
+                       newval = search_def_and_create_phis(user_block, mode, 1);
                }
 
                /* don't fix newly created Phis from the SSA construction */
@@ -240,6 +241,7 @@ static ir_node *copy_and_fix_node(const condeval_env_t *env, ir_node *block,
                        } else {
                                new_pred = copy_and_fix_node(env, block, copy_block, j, pred);
                        }
+                       DB((dbg, LEVEL_2, ">> Set Pred of %+F to %+F\n", copy, new_pred));
                        set_irn_n(copy, i, new_pred);
                }
        }
@@ -316,9 +318,8 @@ static void copy_and_fix(const condeval_env_t *env, ir_node *block,
 
        /* fix data-flow (and reconstruct SSA if needed) */
        foreach_out_edge(block, edge) {
-               ir_node *vals[2];
-               ir_node *blocks[2];
                ir_node *node = get_edge_src_irn(edge);
+               ir_node *copy_node;
                ir_mode *mode;
 
                if (is_Block(node)) {
@@ -337,11 +338,8 @@ static void copy_and_fix(const condeval_env_t *env, ir_node *block,
 
                DB((dbg, LEVEL_2, ">> Fixing users of %+F\n", node));
 
-               blocks[0] = block;
-               vals[0] = node;
-               blocks[1] = copy_block;
-               vals[1] = get_irn_link(node);
-               construct_ssa(blocks, vals, 2);
+               copy_node = get_irn_link(node);
+               construct_ssa(block, node, copy_block, copy_node);
        }
 }