Replace if/else if cascade with switch(opcode)
[libfirm] / ir / ana / irconsconfirm.c
index 6ccc21e..a25e7fb 100644 (file)
@@ -24,9 +24,7 @@
  * @date     6.2005
  * @version  $Id$
  */
-#ifdef HAVE_CONFIG_H
-# include "config.h"
-#endif
+#include "config.h"
 
 #include "irgraph_t.h"
 #include "irnode_t.h"
 #include "irgwalk.h"
 #include "irprintf.h"
 #include "irgopt.h"
+#include "irpass.h"
 #include "irtools.h"
+#include "array_t.h"
+#include "debug.h"
+#include "irflag.h"
 
 /**
  * Walker environment.
  */
 typedef struct _env_t {
-  unsigned num_confirms;  /**< number of inserted Confirm nodes */
-  unsigned num_consts;    /**< number of constants placed */
-  unsigned num_eq;        /**< number of equalities placed */
+       unsigned num_confirms;  /**< Number of inserted Confirm nodes. */
+       unsigned num_consts;    /**< Number of constants placed. */
+       unsigned num_eq;        /**< Number of equalities placed. */
+       unsigned num_non_null;  /**< Number of non-null Confirms. */
 } env_t;
 
+/** The debug handle. */
+DEBUG_ONLY(static firm_dbg_module_t *dbg;)
+
 /**
  * Return the effective use block of a node and it's predecessor on
  * position pos.
@@ -57,10 +63,12 @@ typedef struct _env_t {
  *
  * This handles correctly Phi nodes.
  */
-static ir_node *get_effective_use_block(ir_node *node, int pos) {
+static ir_node *get_effective_use_block(ir_node *node, int pos)
+{
        if (is_Phi(node)) {
-               /* the effective use of a Phi is in its predecessor block */
-               node = get_irn_n(node, pos);
+               /* the effective use of a Phi argument is in its predecessor block */
+               node = get_nodes_block(node);
+               return get_Block_cfgpred_block(node, pos);
        }
        return get_nodes_block(node);
 }
@@ -76,7 +84,8 @@ static ir_node *get_effective_use_block(ir_node *node, int pos) {
  * Branch labels are a simple case. We can replace the value
  * by a Const with the branch label.
  */
-static void handle_case(ir_node *block, ir_node *irn, long nr, env_t *env) {
+static void handle_case(ir_node *block, ir_node *irn, long nr, env_t *env)
+{
        const ir_edge_t *edge, *next;
        ir_node *c = NULL;
 
@@ -102,12 +111,12 @@ static void handle_case(ir_node *block, ir_node *irn, long nr, env_t *env) {
                                ir_mode *mode = get_irn_mode(irn);
                                ir_type *tp   = get_irn_type(irn);
                                tarval *tv    = new_tarval_from_long(nr, mode);
-                               c = new_r_Const_type(current_ir_graph, block, mode, tv, tp);
+                               c = new_r_Const_type(current_ir_graph, tv, tp);
                        }
 
                        set_irn_n(succ, pos, c);
                        DBG_OPT_CONFIRM_C(irn, c);
-//                     ir_printf("1 Replacing input %d of node %n with %n\n", pos, succ, c);
+                       DB((dbg, LEVEL_2, "Replacing input %d of node %+F with %+F\n", pos, succ, c));
 
                        env->num_consts += 1;
                }
@@ -122,8 +131,9 @@ static void handle_case(ir_node *block, ir_node *irn, long nr, env_t *env) {
  * @param pnc       the true/false condition branch
  * @param env       statistical environment
  */
-static void handle_modeb(ir_node *block, ir_node *selector, pn_Cond pnc, env_t *env) {
-       ir_node *cond, *old, *cond_block, *other_blk = NULL, *con = NULL;
+static void handle_modeb(ir_node *block, ir_node *selector, pn_Cond pnc, env_t *env)
+{
+       ir_node *cond, *old, *cond_block = NULL, *other_blk = NULL, *con = NULL;
        ir_node *c_b = NULL, *c_o = NULL;
        const ir_edge_t *edge, *next;
 
@@ -140,13 +150,13 @@ static void handle_modeb(ir_node *block, ir_node *selector, pn_Cond pnc, env_t *
                         * We can replace the input with true/false.
                         */
                        if (con == NULL) {
-                               con = new_Const(mode_b, pnc == pn_Cond_true ? tarval_b_true : tarval_b_false);
+                               con = new_Const(pnc == pn_Cond_true ? tarval_b_true : tarval_b_false);
                        }
                        old = get_irn_n(user, pos);
                        set_irn_n(user, pos, con);
                        DBG_OPT_CONFIRM_C(old, con);
 
-                       // ir_printf("2 Replacing input %d of node %n with %n\n", pos, user, con);
+                       DB((dbg, LEVEL_2, "Replacing input %d of node %+F with %+F\n", pos, user, con));
 
                        env->num_consts += 1;
                } else {
@@ -172,7 +182,7 @@ static void handle_modeb(ir_node *block, ir_node *selector, pn_Cond pnc, env_t *
                                 * block. In that case the other_block is the user_blk itself and pred_block
                                 * is the cond_block ...
                                 *
-                                * Best would be to indroduce a block here, removing this critical edge.
+                                * Best would be to introduce a block here, removing this critical edge.
                                 * For some reasons I cannot repair dominance here, so I have to remove
                                 * ALL critical edges...
                                 * FIXME: This should not be needed if we could repair dominance ...
@@ -201,12 +211,15 @@ static void handle_modeb(ir_node *block, ir_node *selector, pn_Cond pnc, env_t *
                                NEW_ARR_A(ir_node *, in, n);
                                /* ok, ALL predecessors are either dominated by block OR other block */
                                if (c_b == NULL) {
-                                       ir_node *c_true  = new_Const(mode_b, tarval_b_true);
-                                       ir_node *c_false = new_Const(mode_b, tarval_b_false);
-                                       c_b = new_r_Confirm(current_ir_graph, cond_block, selector,
-                                               pnc == pn_Cond_true ? c_true : c_false, pn_Cmp_Eq);
-                                       c_o = new_r_Confirm(current_ir_graph, cond_block, selector,
-                                               pnc == pn_Cond_false ? c_true : c_false, pn_Cmp_Eq);
+                                       ir_node *c_true  = new_Const(tarval_b_true);
+                                       ir_node *c_false = new_Const(tarval_b_false);
+                                       if (pnc == pn_Cond_true) {
+                                               c_b = c_true;
+                                               c_o = c_false;
+                                       } else {
+                                               c_b = c_false;
+                                               c_o = c_true;
+                                       }
                                }
                                for (i = n - 1; i >= 0; --i) {
                                        ir_node *pred_blk = get_Block_cfgpred_block(user_blk, i);
@@ -216,7 +229,7 @@ static void handle_modeb(ir_node *block, ir_node *selector, pn_Cond pnc, env_t *
                                        else
                                                in[i] = c_o;
                                }
-                               phi = new_r_Phi(current_ir_graph, user_blk, n, in, mode_b);
+                               phi = new_r_Phi(user_blk, n, in, mode_b);
                                set_irn_n(user, pos, phi);
                        }
                }
@@ -231,7 +244,8 @@ static void handle_modeb(ir_node *block, ir_node *selector, pn_Cond pnc, env_t *
  * @param pnc     the Compare relation for taking this branch
  * @param env     statistical environment
  */
-static void handle_if(ir_node *block, ir_node *cmp, pn_Cmp pnc, env_t *env) {
+static void handle_if(ir_node *block, ir_node *cmp, pn_Cmp pnc, env_t *env)
+{
        ir_node *left  = get_Cmp_left(cmp);
        ir_node *right = get_Cmp_right(cmp);
        ir_node *cond_block;
@@ -280,7 +294,7 @@ static void handle_if(ir_node *block, ir_node *cmp, pn_Cmp pnc, env_t *env) {
                                set_irn_n(user, pos, right);
                                DBG_OPT_CONFIRM(left, right);
 
-//                             ir_printf("2 Replacing input %d of node %n with %n\n", pos, user, right);
+                               DB((dbg, LEVEL_2, "Replacing input %d of node %+F with %+F\n", pos, user, right));
 
                                env->num_eq += 1;
                        } else if (block_dominates(blk, cond_block)) {
@@ -323,12 +337,11 @@ static void handle_if(ir_node *block, ir_node *cmp, pn_Cmp pnc, env_t *env) {
        } else { /* not pn_Cmp_Eq cases */
                ir_node *c = NULL;
 
-               for (edge = get_irn_out_edge_first(left); edge; edge = next) {
+               foreach_out_edge_safe(left, edge, next) {
                        ir_node *succ = get_edge_src_irn(edge);
                        int     pos   = get_edge_src_pos(edge);
                        ir_node *blk  = get_effective_use_block(succ, pos);
 
-                       next = get_irn_out_edge_next(left, edge);
                        if (block_dominates(block, blk)) {
                                /*
                                 * Ok, we found a usage of left in a block
@@ -336,22 +349,57 @@ static void handle_if(ir_node *block, ir_node *cmp, pn_Cmp pnc, env_t *env) {
                                 * We can replace the input with a Confirm(left, pnc, right).
                                 */
                                if (! c)
-                                       c = new_r_Confirm(current_ir_graph, block, left, right, pnc);
+                                       c = new_r_Confirm(block, left, right, pnc);
 
                                pos = get_edge_src_pos(edge);
                                set_irn_n(succ, pos, c);
-//                             ir_printf("3 Replacing input %d of node %n with %n\n", pos, user, c);
+                               DB((dbg, LEVEL_2, "Replacing input %d of node %+F with %+F\n", pos, succ, c));
 
                                env->num_confirms += 1;
                        }
                }
+
+               if (! is_Const(right)) {
+                       /* also construct inverse Confirms */
+                       ir_node *rc = NULL;
+
+                       pnc = get_inversed_pnc(pnc);
+                       foreach_out_edge_safe(right, edge, next) {
+                               ir_node *succ = get_edge_src_irn(edge);
+                               int     pos;
+                               ir_node *blk;
+
+                               if (succ == c)
+                                       continue;
+
+                               pos  = get_edge_src_pos(edge);
+                               blk  = get_effective_use_block(succ, pos);
+
+                               if (block_dominates(block, blk)) {
+                                       /*
+                                        * Ok, we found a usage of right in a block
+                                        * dominated by the branch block.
+                                        * We can replace the input with a Confirm(right, pnc^-1, left).
+                                        */
+                                       if (! rc)
+                                               rc = new_r_Confirm(block, right, left, pnc);
+
+                                       pos = get_edge_src_pos(edge);
+                                       set_irn_n(succ, pos, rc);
+                                       DB((dbg, LEVEL_2, "Replacing input %d of node %+F with %+F\n", pos, succ, rc));
+
+                                       env->num_confirms += 1;
+                               }
+                       }
+               }
        }
 }  /* handle_if */
 
 /**
- * Pre-walker: Called for every block to insert Confirm nodes
+ * Pre-block-walker: Called for every block to insert Confirm nodes
  */
-static void insert_Confirm(ir_node *block, void *env) {
+static void insert_Confirm_in_block(ir_node *block, void *env)
+{
        ir_node *cond, *proj, *selector;
        ir_mode *mode;
 
@@ -380,40 +428,144 @@ static void insert_Confirm(ir_node *block, void *env) {
                handle_modeb(block, selector, get_Proj_proj(proj), env);
 
                /* this should be an IF, check this */
-               if (get_irn_op(selector) != op_Proj)
+               if (! is_Proj(selector))
                        return;
 
                cmp = get_Proj_pred(selector);
-               if (get_irn_op(cmp) != op_Cmp)
+               if (! is_Cmp(cmp))
                        return;
 
                pnc = get_Proj_proj(selector);
 
                if (get_Proj_proj(proj) != pn_Cond_true) {
                        /* it's the false branch */
+                       mode = get_irn_mode(get_Cmp_left(cmp));
                        pnc = get_negated_pnc(pnc, mode);
                }
-//             ir_printf("At %n using %n Confirm %=\n", block, cmp, pnc);
+               DB((dbg, LEVEL_2, "At %+F using %+F Confirm %=\n", block, cmp, pnc));
 
                handle_if(block, cmp, pnc, env);
        } else if (mode_is_int(mode)) {
                long proj_nr = get_Proj_proj(proj);
 
                /* this is a CASE, but we cannot handle the default case */
-               if (proj_nr == get_Cond_defaultProj(cond))
+               if (proj_nr == get_Cond_default_proj(cond))
                        return;
 
                handle_case(block, get_Cond_selector(cond), proj_nr, env);
        }
+}  /* insert_Confirm_in_block */
+
+/**
+ * Checks if a node is a non-null Confirm.
+ */
+static int is_non_null_Confirm(const ir_node *ptr)
+{
+       for (;;) {
+               if (! is_Confirm(ptr))
+                       break;
+               if (get_Confirm_cmp(ptr) == pn_Cmp_Lg) {
+                       ir_node *bound = get_Confirm_bound(ptr);
+
+                       if (is_Const(bound) && is_Const_null(bound))
+                               return 1;
+               }
+               ptr = get_Confirm_value(ptr);
+       }
+       /*
+        * While a SymConst is not a Confirm, it is non-null
+        * anyway. This helps to reduce the number of
+        * constructed Confirms.
+        */
+       if (is_SymConst_addr_ent(ptr))
+               return 1;
+       return 0;
+}  /* is_non_null_Confirm */
+
+/**
+ * The given pointer will be dereferenced, add non-null Confirms.
+ *
+ * @param ptr    a node representing an address
+ * @param block  the block of the dereferencing instruction
+ * @param env    environment
+ */
+static void insert_non_null(ir_node *ptr, ir_node *block, env_t *env)
+{
+       const ir_edge_t *edge, *next;
+       ir_node         *c = NULL;
+
+       foreach_out_edge_safe(ptr, edge, next) {
+               ir_node *succ = get_edge_src_irn(edge);
+               int     pos;
+               ir_node *blk;
+
+
+               /* for now, we place a Confirm only in front of a Cmp */
+               if (! is_Cmp(succ))
+                       continue;
+
+               pos = get_edge_src_pos(edge);
+               blk = get_effective_use_block(succ, pos);
+
+               if (block_dominates(block, blk)) {
+                       /*
+                        * Ok, we found a usage of ptr in a block
+                        * dominated by the Load/Store block.
+                        * We can replace the input with a Confirm(ptr, !=, NULL).
+                        */
+                       if (c == NULL) {
+                               ir_mode *mode = get_irn_mode(ptr);
+                               c = new_Const(get_mode_null(mode));
+
+                               c = new_r_Confirm(block, ptr, c, pn_Cmp_Lg);
+                       }
+
+                       set_irn_n(succ, pos, c);
+                       DB((dbg, LEVEL_2, "Replacing input %d of node %+F with %+F\n", pos, succ, c));
+
+                       env->num_non_null += 1;
+                       env->num_confirms += 1;
+               }
+       }
+}  /* insert_non_null */
+
+/**
+ * Pre-walker: Called for every node to insert Confirm nodes
+ */
+static void insert_Confirm(ir_node *node, void *env)
+{
+       ir_node *ptr;
+
+       switch (get_irn_opcode(node)) {
+       case iro_Block:
+               insert_Confirm_in_block(node, env);
+               break;
+       case iro_Load:
+               ptr = get_Load_ptr(node);
+               if (! is_non_null_Confirm(ptr))
+                       insert_non_null(ptr, get_nodes_block(node), env);
+               break;
+       case iro_Store:
+               ptr = get_Store_ptr(node);
+               if (! is_non_null_Confirm(ptr))
+                       insert_non_null(ptr, get_nodes_block(node), env);
+               break;
+       default:
+               break;
+       }
 }  /* insert_Confirm */
 
 /*
  * Construct Confirm nodes
  */
-void construct_confirms(ir_graph *irg) {
+void construct_confirms(ir_graph *irg)
+{
        env_t env;
        int edges_active = edges_activated(irg);
 
+
+       FIRM_DBG_REGISTER(dbg, "firm.ana.confirm");
+
        remove_critical_cf_edges(irg);
 
        /* we need dominance info */
@@ -430,9 +582,15 @@ void construct_confirms(ir_graph *irg) {
        env.num_confirms = 0;
        env.num_consts   = 0;
        env.num_eq       = 0;
-
-       /* now, visit all blocks and add Confirms where possible */
-       irg_block_walk_graph(irg, insert_Confirm, NULL, &env);
+       env.num_non_null = 0;
+
+       if (get_opt_global_null_ptr_elimination()) {
+               /* do global NULL test elimination */
+               irg_walk_graph(irg, insert_Confirm, NULL, &env);
+       } else {
+               /* now, visit all blocks and add Confirms where possible */
+               irg_block_walk_graph(irg, insert_Confirm_in_block, NULL, &env);
+       }
 
        if (env.num_confirms | env.num_consts | env.num_eq) {
                /* we have add nodes or changed DF edges */
@@ -442,40 +600,58 @@ void construct_confirms(ir_graph *irg) {
                set_irg_loopinfo_inconsistent(irg);
        }
 
-#if 0
-       printf("# Confirms inserted : %u\n", env.num_confirms);
-       printf("# Const replacements: %u\n", env.num_consts);
-       printf("# node equalities   : %u\n", env.num_eq);
-#endif
+       DB((dbg, LEVEL_1, "# Confirms inserted : %u\n", env.num_confirms));
+       DB((dbg, LEVEL_1, "# Const replacements: %u\n", env.num_consts));
+       DB((dbg, LEVEL_1, "# node equalities   : %u\n", env.num_eq));
+       DB((dbg, LEVEL_1, "# non-null Confirms : %u\n", env.num_non_null));
 
        /* deactivate edges if they where off */
        if (! edges_active)
                edges_deactivate(irg);
 }  /* construct_confirms */
 
+/* Construct a pass. */
+ir_graph_pass_t *construct_confirms_pass(const char *name)
+{
+       return def_graph_pass(name ? name : "confirm", construct_confirms);
+}  /* construct_confirms_pass */
+
+#if 0
 /**
  * Post-walker: Remove Confirm nodes
  */
-static void rem_Confirm(ir_node *n, void *env) {
+static void rem_Confirm(ir_node *n, void *env)
+{
        (void) env;
-       if (get_irn_op(n) == op_Confirm) {
+       if (is_Confirm(n)) {
                ir_node *value = get_Confirm_value(n);
                if (value != n)
                        exchange(n, value);
                else {
                        /*
-                        * Strange: a Confirm is it's own bound. This can happen
+                        * Strange: a Confirm is its own bound. This can happen
                         * in dead blocks when Phi nodes are already removed.
                         */
                        exchange(n, new_Bad());
                }
        }
 }  /* rem_Confirm */
+#endif
 
 /*
  * Remove all Confirm nodes from a graph.
  */
-void remove_confirms(ir_graph *irg) {
+void remove_confirms(ir_graph *irg)
+{
+       int rem = get_opt_remove_confirm();
+
        set_opt_remove_confirm(1);
        optimize_graph_df(irg);
+       set_opt_remove_confirm(rem);
 }  /* remove_confirms */
+
+/* Construct a pass. */
+ir_graph_pass_t *remove_confirms_pass(const char *name)
+{
+       return def_graph_pass(name ? name : "rem_confirm", remove_confirms);
+}  /* remove_confirms_pass */