Construction of Confirm nodes

[r6046]

diff --git a/ir/ana/irconsconfirm.c b/ir/ana/irconsconfirm.c
new file mode 100644 (file)
index 0000000..0a9f250
--- /dev/null
+++ b/ir/ana/irconsconfirm.c
@@ -0,0 +1,279 @@
+/*
+ * Project:     libFIRM
+ * File name:   ir/ana/irconsconfirm.c
+ * Purpose:     Construction of Confirm nodes
+ * Author:      Michael Beck
+ * Modified by:
+ * Created:     6.2005
+ * CVS-ID:      $Id$
+ * Copyright:   (C) 2002-2005 Universität Karlsruhe
+ * Licence:     This file protected by GPL -  GNU GENERAL PUBLIC LICENSE.
+ */
+
+/**
+ * @file irconsconfirm.c
+ *
+ * Construction of Confirm nodes
+ *
+ * @author Michael Beck
+ */
+#include "irgraph_t.h"
+#include "irnode_t.h"
+#include "ircons_t.h"
+#include "irgmod.h"
+#include "iropt_dbg.h"
+#include "iredges_t.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 */
+} env_t;
+
+/**
+ * Handle a CASE-branch.
+ *
+ * @param block   the block which is entered by the branch
+ * @param irn     the node expressing the switch value
+ * @param pnc     the branch label
+ * @param env     statistical environment
+ *
+ * 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)
+{
+  int pos;
+  const ir_edge_t *edge, *next;
+  ir_node *c = NULL;
+
+  for (edge = get_irn_out_edge_first(irn); edge; edge = next) {
+    ir_node *succ = get_edge_src_irn(edge);
+    ir_node *blk = get_nodes_block(succ);
+
+    next = get_irn_out_edge_next(irn, edge);
+
+    if (block_dominates(block, blk)) {
+      /*
+       * Ok, we found a user of irn that is placed
+       * in a block dominated by the branch block.
+       * We can replace the input with the Constant
+       * branch label.
+       */
+
+      if (! c) {
+        ir_mode *mode = get_irn_mode(irn);
+        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);
+      }
+
+      pos = get_edge_src_pos(edge);
+      set_irn_n(succ, pos, c);
+      DBG_OPT_CONFIRM(irn, c);
+
+      env->num_consts += 1;
+    }
+  }
+}
+
+/**
+ * Handle an IF-branch.
+ *
+ * @param block   the block which is entered by the branch
+ * @param cmp     the Cmp node expressing the branch condition
+ * @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)
+{
+  ir_node *left  = get_Cmp_left(cmp);
+  ir_node *right = get_Cmp_right(cmp);
+  const ir_edge_t *edge, *next;
+
+  /* remove unordered if it's an integer compare */
+  if (mode_is_int(get_irn_mode(left)))
+    pnc &= ~pn_Cmp_Uo;
+
+  /* try to place the constant on the right side */
+  if (get_irn_op(left) == op_Const) {
+    ir_node *t = left;
+
+    left  = right;
+    right = t;
+
+    pnc = get_inversed_pnc(pnc);
+  }
+
+  /*
+   * First case: both values are identical.
+   * replace the left one by the right one.
+   */
+  if (pnc == pn_Cmp_Eq) {
+    int pos;
+
+    for (edge = get_irn_out_edge_first(left); edge; edge = next) {
+      ir_node *succ = get_edge_src_irn(edge);
+      ir_node *blk = get_nodes_block(succ);
+
+      next = get_irn_out_edge_next(left, edge);
+      if (block_dominates(block, blk)) {
+        /*
+         * Ok, we found a user of left that is placed
+         * in a block dominated by the branch block.
+         * We can replace the input with right.
+         */
+        pos = get_edge_src_pos(edge);
+        set_irn_n(succ, pos, right);
+        DBG_OPT_CONFIRM(left, right);
+
+        env->num_eq += 1;
+      }
+    }
+  }
+  else { /* not == cases */
+    int pos;
+    ir_node *c = NULL;
+
+    for (edge = get_irn_out_edge_first(left); edge; edge = next) {
+      ir_node *succ = get_edge_src_irn(edge);
+      ir_node *blk = get_nodes_block(succ);
+
+      next = get_irn_out_edge_next(left, edge);
+      if (block_dominates(block, blk)) {
+        /*
+         * Ok, we found a user of left that is placed
+         * in a block dominated by the branch block.
+         * We can replace the input with a Confirm(left, pnc, right).
+         */
+
+        if (! c)
+          c = new_r_Confirm(current_ir_graph, block, left, right, pnc);
+
+        pos = get_edge_src_pos(edge);
+        set_irn_n(succ, pos, c);
+        DBG_OPT_CONFIRM(left, c);
+
+        env->num_confirms += 1;
+      }
+    }
+  }
+}
+
+/**
+ * Pre-walker: Called for every block to insert Confirm nodes
+ */
+static void insert_Confirm(ir_node *block, void *env)
+{
+  ir_node *cond, *proj, *selector;
+  ir_mode *mode;
+
+  /*
+   * we can only handle blocks with only ONE control flow
+   * predecessor
+   */
+  if (get_Block_n_cfgpreds(block) != 1)
+    return;
+
+  proj = get_Block_cfgpred(block, 0);
+  if (get_irn_op(proj) != op_Proj)
+    return;
+
+  cond = get_Proj_pred(proj);
+  if (get_irn_op(cond) != op_Cond)
+    return;
+
+  selector = get_Cond_selector(cond);
+  mode = get_irn_mode(selector);
+
+  if (mode == mode_b) {
+    ir_node *cmp;
+    pn_Cmp pnc;
+
+    /* this should be an IF, check this */
+    if (get_irn_op(selector) != op_Proj)
+      return;
+
+    cmp = get_Proj_pred(selector);
+    if (get_irn_op(cmp) != op_Cmp)
+      return;
+
+    pnc = get_Proj_proj(selector);
+
+    if (get_Proj_proj(proj) != pn_Cond_true) {
+      /* it's the false branch */
+      pnc = get_negated_pnc(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))
+      return;
+
+    handle_case(block, get_Cond_selector(cond), proj_nr, env);
+  }
+}
+
+/*
+ * Construct Confirm nodes
+ */
+void construct_confirms(ir_graph *irg)
+{
+  env_t env;
+  int edges_active = edges_activated(irg);
+
+  if (get_irg_dom_state(irg) != dom_consistent) {
+    /* we need dominance info */
+    compute_doms(irg);
+  }
+
+  if (! edges_active) {
+    /* We need edges */
+    edges_activate(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);
+
+  if (env.num_confirms | env.num_consts | env.num_eq) {
+    /* we have add nodes or changed DF edges */
+    set_irg_outs_inconsistent(irg);
+
+    /* the new nodes are not in the loop info */
+    set_irg_loopinfo_inconsistent(irg);
+  }
+
+  printf("No Confirms inserted : %u\n", env.num_confirms);
+  printf("No Const replacements: %u\n", env.num_consts);
+  printf("No node equalities   : %u\n", env.num_eq);
+
+  /* deactivate edges if they where off */
+  if (! edges_active)
+    edges_deactivate(irg);
+}
+
+/**
+ * Post-walker: Remove COnfirm nodes
+ */
+static void rem_Confirm(ir_node *n, void *env) {
+  if (get_irn_op(n) == op_Confirm) {
+    exchange(n, get_Confirm_value(n));
+  }
+}
+
+/*
+ * Remove all Confirm nodes from a graph.
+ */
+void remove_confirms(ir_graph *irg) {
+  irg_walk_graph(irg, NULL, rem_Confirm, NULL);
+}

diff --git a/ir/ana/irconsconfirm.h b/ir/ana/irconsconfirm.h
new file mode 100644 (file)
index 0000000..2e0aa95
--- /dev/null
+++ b/ir/ana/irconsconfirm.h
@@ -0,0 +1,55 @@
+/*
+ * Project:     libFIRM
+ * File name:   ir/ana/irconsconfirm.h
+ * Purpose:     Construction of Confirm nodes
+ * Author:      Michael Beck
+ * Modified by:
+ * Created:     6.2005
+ * CVS-ID:      $Id$
+ * Copyright:   (C) 2002-2005 Universität Karlsruhe
+ * Licence:     This file protected by GPL -  GNU GENERAL PUBLIC LICENSE.
+ */
+
+/**
+ * @file irconsconfirm.h
+ *
+ *  Construction of Confirm nodes
+ *
+ *  @author Michael Beck
+ */
+#ifndef _IRCONSCONFIRM_H_
+#define _IRCONSCONFIRM_H_
+
+#include "irgraph.h"
+
+/*
+ * Inject Confirm nodes into a graph.
+ *
+ * @param irg  the graph
+ *
+ * Confirm nodes carry confirmation information, such as
+ * a relation between a value a and another value (or a constant)
+ * b.
+ *
+ * These allows to do some range dependent optimizations for Cmp,
+ * Abs, Min, Max nodes as well as bounds checking removement.
+ *
+ * The heap analysis might profit also. On the other side, Confirm
+ * nodes disturb local optimizations, because patterns are destroyed.
+ *
+ * It is possible to avoid this by skipping Confirm nodes, but this
+ * is not implemented and is not cheap. The same happens with Casts
+ * nodes too. The current solution is to remove Confirms at a later
+ * pass.
+ */
+void construct_confirms(ir_graph *irg);
+
+/**
+ * Remove all Confirm nodes from a graph.
+ *
+ * Note that local_optimize() can handle this if
+ * the remove Confirm node setting is on (set_opt_remove_Confirm(1)).
+ */
+void remove_confirms(ir_graph *irg);
+
+#endif /* _IRCONSCONFIRM_H_ */