/*
- * Project: libFIRM
- * File name: ir/ana/irscc.c
- * Purpose: Compute the strongly connected regions and build
+ * This file is part of libFirm.
+ * Copyright (C) 2012 University of Karlsruhe.
+ */
+
+/**
+ * @file
+ * @brief Compute the strongly connected regions and build
* backedge/loop datastructures.
* A variation on the Tarjan algorithm. See also [Trapp:99],
* Chapter 5.2.1.2.
- * Author: Goetz Lindenmaier
- * Modified by:
- * Created: 7.2002
- * CVS-ID: $Id$
- * Copyright: (c) 2002-2003 Universität Karlsruhe
- * Licence: This file protected by GPL - GNU GENERAL PUBLIC LICENSE.
+ * @author Goetz Lindenmaier
+ * @date 7.2002
*/
-
-#ifdef HAVE_CONFIG_H
#include "config.h"
-#endif
#include <string.h>
+#include <stdlib.h>
#include "irloop_t.h"
-#include "irnode_t.h"
+
+#include "irprog_t.h"
#include "irgraph_t.h"
-#include "array.h"
-#include "pmap.h"
+#include "irnode_t.h"
#include "irgwalk.h"
-#include "irprog_t.h"
#include "irdump.h"
-
-ir_graph *outermost_ir_graph; /* The outermost graph the scc is computed
- for */
-static ir_loop *current_loop; /* Current loop construction is working
- on. */
-static int loop_node_cnt = 0; /* Counts the number of allocated loop nodes.
- Each loop node gets a unique number.
- What for? ev. remove. @@@ */
-static int current_dfn = 1; /* Counter to generate depth first numbering
- of visited nodes. */
-
-void link_to_reg_end (ir_node *n, void *env);
-void set_projx_link(ir_node *cb_projx, ir_node *end_projx);
-ir_node *get_projx_link(ir_node *cb_projx);
-
-/**********************************************************************/
-/* Node attributes **/
-/**********************************************************************/
-
-/* A map to get from irnodes to loop nodes. */
-static pmap *node_loop_map = NULL;
+#include "array.h"
+#include "pmap.h"
+#include "ircons.h"
+
+/** The outermost graph the scc is computed for. */
+static ir_graph *outermost_ir_graph;
+/** Current loop construction is working on. */
+static ir_loop *current_loop;
+/** Counts the number of allocated loop nodes.
+ * Each loop node gets a unique number.
+ * @todo What for? ev. remove.
+ */
+static int loop_node_cnt = 0;
+/** Counter to generate depth first numbering of visited nodes. */
+static int current_dfn = 1;
/**********************************************************************/
/* Node attributes needed for the construction. **/
/**********************************************************************/
typedef struct scc_info {
- bool in_stack; /* Marks whether node is on the stack. */
- int dfn; /* Depth first search number. */
- int uplink; /* dfn number of ancestor. */
- /* ir_loop *loop; *//* Refers to the containing loop. */
- /*
- struct section *section;
- xset def;
- xset use;
- */
+ int in_stack; /**< Marks whether node is on the stack. */
+ int dfn; /**< Depth first search number. */
+ int uplink; /**< dfn number of ancestor. */
} scc_info;
-static INLINE scc_info* new_scc_info(void) {
- scc_info *info = obstack_alloc (outermost_ir_graph->obst, sizeof (scc_info));
- memset (info, 0, sizeof (scc_info));
- return info;
-}
-
-static INLINE void
-mark_irn_in_stack (ir_node *n) {
- assert(get_irn_link(n));
- /* to slow */
- /* ((scc_info *)get_irn_link(n))->in_stack = true; */
- ((scc_info *)n->link)->in_stack = true;
-}
-
-static INLINE void
-mark_irn_not_in_stack (ir_node *n) {
- assert(get_irn_link(n));
- /* to slow */
- /* ((scc_info *)get_irn_link(n))->in_stack = false; */
- ((scc_info *)n->link)->in_stack = false;
-}
-
-static INLINE bool
-irn_is_in_stack (ir_node *n) {
- assert(get_irn_link(n));
- /* to slow */
- /* return ((scc_info *)get_irn_link(n))->in_stack; */
- return ((scc_info *)n->link)->in_stack;
-}
-
-static INLINE void
-set_irn_uplink (ir_node *n, int uplink) {
- assert(get_irn_link(n));
- /* to slow */
- /* ((scc_info *)get_irn_link(n))->uplink = uplink; */
- ((scc_info *)n->link)->uplink = uplink;
-}
-
-static INLINE int
-get_irn_uplink (ir_node *n) {
- assert(get_irn_link(n));
- /* from fast to slow */
- /* return ((scc_info *)get_irn_link(n))->uplink; */
- return ((scc_info *)n->link)->uplink;
+/**
+ * Allocates a new SCC info on the given obstack.
+ */
+static inline scc_info *new_scc_info(struct obstack *obst)
+{
+ return OALLOCZ(obst, scc_info);
}
-static INLINE void
-set_irn_dfn (ir_node *n, int dfn) {
- assert(get_irn_link(n));
- /* to slow */
- /* ((scc_info *)get_irn_link(n))->dfn = dfn; */
- ((scc_info *)n->link)->dfn = dfn;
+/**
+ * Mark node n being on the SCC stack.
+ */
+static inline void mark_irn_in_stack(ir_node *n)
+{
+ scc_info *scc = (scc_info*) get_irn_link(n);
+ assert(scc);
+ scc->in_stack = 1;
}
-static INLINE int
-get_irn_dfn (ir_node *n) {
- assert(get_irn_link(n));
- /* to slow */
- /* return ((scc_info *)get_irn_link(n))->dfn; */
- return ((scc_info *)n->link)->dfn;
+/**
+* Mark node n NOT being on the SCC stack.
+*/
+static inline void mark_irn_not_in_stack(ir_node *n)
+{
+ scc_info *scc = (scc_info*) get_irn_link(n);
+ assert(scc);
+ scc->in_stack = 0;
}
-#if 0
-/* Replaced node loop map by real field as hash access dominates runtime
- * of the algorithm. ! */
-/* Uses temporary information to set the loop */
-static INLINE void
-set_irn_loop (ir_node *n, ir_loop* loop) {
- assert(node_loop_map && "not initialized!");
- pmap_insert(node_loop_map, (void *)n, (void *)loop);
+/**
+ * Checks if a node is on the SCC stack.
+ */
+static inline int irn_is_in_stack(ir_node *n)
+{
+ scc_info *scc = (scc_info*) get_irn_link(n);
+ assert(scc);
+ return scc->in_stack;
}
-/* Uses temporary information to get the loop */
-INLINE ir_loop *
-get_irn_loop (ir_node *n) {
- ir_loop *res = NULL;
- if (!node_loop_map) return NULL;
-
- if (pmap_contains(node_loop_map, (void *)n))
- res = (ir_loop *) pmap_get(node_loop_map, (void *)n);
-
- return res;
-}
-#else
-static INLINE void
-set_irn_loop (ir_node *n, ir_loop* loop) {
- n->loop = loop;
+/**
+ * Sets the uplink number for a node.
+ */
+static inline void set_irn_uplink(ir_node *n, int uplink)
+{
+ scc_info *scc = (scc_info*) get_irn_link(n);
+ assert(scc);
+ scc->uplink = uplink;
}
-/* Uses temporary information to get the loop */
-INLINE ir_loop *
-get_irn_loop (ir_node *n) {
- return n->loop;
+/**
+ * Returns the uplink number for a node.
+ */
+static int get_irn_uplink(ir_node *n)
+{
+ scc_info *scc = (scc_info*) get_irn_link(n);
+ assert(scc);
+ return scc->uplink;
}
-#endif
-
-
-#if 0
-static ir_loop *find_nodes_loop (ir_node *n, ir_loop *l) {
- int i;
- ir_loop *res = NULL;
-
- /* Test whether n is contained in this loop. */
- for (i = 0; i < get_loop_n_nodes(l); i++)
- if (n == get_loop_node(l, i)) return l;
-
- /* Is this a leave in the loop tree? If so loop not found. */
- if (get_loop_n_sons(l) == 0) return NULL;
- /* Else descend in the loop tree. */
- for (i = 0; i < get_loop_n_sons(l); i++) {
- res = find_nodes_loop(n, get_loop_son(l, i));
- if (res) break;
- }
- return res;
+/**
+ * Sets the depth-first-search number for a node.
+ */
+static inline void set_irn_dfn(ir_node *n, int dfn)
+{
+ scc_info *scc = (scc_info*) get_irn_link(n);
+ assert(scc);
+ scc->dfn = dfn;
}
-/* @@@ temporary implementation, costly!!! */
-ir_loop * get_irn_loop(ir_node *n) {
- ir_loop *l = get_irg_loop(current_ir_graph);
- l = find_nodes_loop(n, l);
- return l;
+/**
+ * Returns the depth-first-search number of a node.
+ */
+static int get_irn_dfn(ir_node *n)
+{
+ scc_info *scc = (scc_info*) get_irn_link(n);
+ assert(scc);
+ return scc->dfn;
}
-#endif
/**********************************************************************/
/* A stack. **/
/**********************************************************************/
static ir_node **stack = NULL;
-static int tos = 0; /* top of stack */
-
-static INLINE void init_stack(void) {
- if (stack) {
- ARR_RESIZE (ir_node *, stack, 1000);
- } else {
- stack = NEW_ARR_F (ir_node *, 1000);
- }
- tos = 0;
+static size_t tos = 0; /* top of stack */
+
+/**
+ * initializes the stack
+ */
+static inline void init_stack(void)
+{
+ if (stack) {
+ ARR_RESIZE(ir_node *, stack, 1000);
+ } else {
+ stack = NEW_ARR_F(ir_node *, 1000);
+ }
+ tos = 0;
}
-#if 0
-static INLINE void free_stack(void) {
- DEL_ARR_F(stack);
- stack = NULL;
- tos = 0;
+/**
+ * Frees the stack.
+ */
+static void finish_stack(void)
+{
+ DEL_ARR_F(stack);
+ stack = NULL;
}
-#endif
-static INLINE void
-push (ir_node *n)
+/**
+ * push a node onto the stack
+ *
+ * @param n The node to push
+ */
+static inline void push(ir_node *n)
{
- /*DDMN(n);*/
-
- if (tos == ARR_LEN (stack)) {
- int nlen = ARR_LEN (stack) * 2;
- ARR_RESIZE (ir_node *, stack, nlen);
- }
- stack [tos++] = n;
- mark_irn_in_stack(n);
+ if (tos == ARR_LEN(stack)) {
+ size_t nlen = ARR_LEN(stack) * 2;
+ ARR_RESIZE(ir_node *, stack, nlen);
+ }
+ stack[tos++] = n;
+ mark_irn_in_stack(n);
}
-static INLINE ir_node *
-pop (void)
+/**
+ * pop a node from the stack
+ *
+ * @return The topmost node
+ */
+static inline ir_node *pop(void)
{
- ir_node *n = stack[--tos];
- mark_irn_not_in_stack(n);
- return n;
+ ir_node *n;
+
+ assert(tos > 0);
+ n = stack[--tos];
+ mark_irn_not_in_stack(n);
+ return n;
}
-/* The nodes up to n belong to the current loop.
- Removes them from the stack and adds them to the current loop. */
-static INLINE void
-pop_scc_to_loop (ir_node *n)
+/**
+ * The nodes up to n belong to the current loop.
+ * Removes them from the stack and adds them to the current loop.
+ */
+static inline void pop_scc_to_loop(ir_node *n)
{
- ir_node *m;
- int i = 0;
-
- /*for (;;) {*/
- do
- {
- m = pop();
- loop_node_cnt++;
- set_irn_dfn(m, loop_node_cnt);
- add_loop_node(current_loop, m);
- set_irn_loop(m, current_loop);
- i++;
- /* if (m==n) break;*/
- } while(m != n);
-
- if(i > 1)
- printf("Mehr als eine Iteration!!!!!!!!!!!!!!!!!!!!!!!!!!!!11111\n");
+ ir_node *m;
+
+ do {
+ m = pop();
+
+ loop_node_cnt++;
+ set_irn_dfn(m, loop_node_cnt);
+ add_loop_node(current_loop, m);
+ set_irn_loop(m, current_loop);
+ } while (m != n);
}
/* GL ??? my last son is my grandson??? Removes loops with no
ir_nodes in them. Such loops have only another loop as son. (Why
can't they have two loops as sons? Does it never get that far? ) */
-void close_loop (ir_loop *l)
+static void close_loop(ir_loop *l)
{
- int last = get_loop_n_elements(l) - 1;
- loop_element lelement = get_loop_element(l, last);
- ir_loop *last_son = lelement.son;
-
- if (get_kind(last_son) == k_ir_loop &&
- get_loop_n_elements(last_son) == 1)
- {
- ir_loop *gson;
-
- lelement = get_loop_element(last_son, 0);
- gson = lelement.son;
- if(get_kind(gson) == k_ir_loop)
- {
- loop_element new_last_son;
-
- gson -> outer_loop = l;
- new_last_son.son = gson;
- l -> children[last] = new_last_son;
- }
- }
-
- current_loop = l;
+ size_t last = get_loop_n_elements(l) - 1;
+ loop_element lelement = get_loop_element(l, last);
+ ir_loop *last_son = lelement.son;
+
+ if (get_kind(last_son) == k_ir_loop &&
+ get_loop_n_elements(last_son) == 1) {
+ ir_loop *gson;
+
+ lelement = get_loop_element(last_son, 0);
+ gson = lelement.son;
+
+ if (get_kind(gson) == k_ir_loop) {
+ loop_element new_last_son;
+
+ gson->outer_loop = l;
+ new_last_son.son = gson;
+ l->children[last] = new_last_son;
+ }
+ }
+
+ current_loop = l;
}
/* Removes and unmarks all nodes up to n from the stack.
The nodes must be visited once more to assign them to a scc. */
-static INLINE void
-pop_scc_unmark_visit (ir_node *n)
+static inline void pop_scc_unmark_visit(ir_node *n)
{
- ir_node *m = NULL;
+ ir_node *m = NULL;
- while (m != n) {
- m = pop();
- set_irn_visited(m, 0);
- }
+ while (m != n) {
+ m = pop();
+ set_irn_visited(m, 0);
+ }
}
/**********************************************************************/
/* Allocates a new loop as son of current_loop. Sets current_loop
to the new loop and returns the father. */
-static ir_loop *new_loop (void) {
- ir_loop *father, *son;
-
- father = current_loop;
-
- son = (ir_loop *) obstack_alloc (outermost_ir_graph->obst, sizeof (ir_loop));
- memset (son, 0, sizeof (ir_loop));
- son->kind = k_ir_loop;
- son->children = NEW_ARR_F (loop_element, 0);
- son->n_nodes = 0;
- son->n_sons=0;
- if (father) {
- son->outer_loop = father;
- add_loop_son(father, son);
- son->depth = father->depth+1;
- } else { /* The root loop */
- son->outer_loop = son;
- son->depth = 0;
- }
-
-#ifdef DEBUG_libfirm
- son->loop_nr = get_irp_new_node_nr();
- son->link = NULL;
-#endif
-
- current_loop = son;
- return father;
-}
-
-#if 0
-/* Finishes the datastructures, copies the arrays to the obstack
- of current_ir_graph.
- A. Schoesser: Caution: loop -> sons is gone. */
-static void mature_loop (ir_loop *loop) {
- ir_loop **new_sons;
-
- new_sons = NEW_ARR_D (ir_loop *, current_ir_graph->obst, ARR_LEN(loop->sons));
- memcpy (new_sons, loop->sons, sizeof (ir_loop *) * ARR_LEN(loop->sons));
- DEL_ARR_F(loop->sons);
- loop->sons = new_sons;
-}
-#endif
-
-/* Returns outer loop, itself if outermost. */
-ir_loop *get_loop_outer_loop (ir_loop *loop) {
- assert(loop && loop->kind == k_ir_loop);
- return loop->outer_loop;
-}
-
-/* Returns nesting depth of this loop */
-int get_loop_depth (ir_loop *loop) {
- assert(loop); assert(loop->kind == k_ir_loop);
- return loop->depth;
-}
-
-/* Returns the number of inner loops */
-int get_loop_n_sons (ir_loop *loop) {
- assert(loop && loop->kind == k_ir_loop);
- return(loop -> n_sons);
-}
-
-/* Returns the pos`th loop_node-child *
- * TODO: This method isn`t very efficient ! *
- * Returns NULL if there isnt`t a pos`th loop_node */
-ir_loop *get_loop_son (ir_loop *loop, int pos) {
- int child_nr = 0, loop_nr = -1;
-
- assert(loop && loop->kind == k_ir_loop);
- while(child_nr < ARR_LEN(loop->children))
- {
- if(*(loop -> children[child_nr].kind) == k_ir_loop)
- loop_nr++;
- if(loop_nr == pos)
- return(loop -> children[child_nr].son);
- child_nr++;
- }
- return NULL;
-}
-
-/* Use EXCLUSIVELY this function to add sons, otherwise the loop->n_sons
- is invalid! */
-
-static INLINE void
-add_loop_son(ir_loop *loop, ir_loop *son) {
- loop_element lson;
- lson.son = son;
- assert(loop && loop->kind == k_ir_loop);
- assert(get_kind(son) == k_ir_loop);
- ARR_APP1 (loop_element, loop->children, lson);
- loop -> n_sons++;
-}
-
-/* Returns the number of nodes in the loop */
-int get_loop_n_nodes (ir_loop *loop) {
- assert(loop); assert(loop->kind == k_ir_loop);
- return loop -> n_nodes;
-/* return ARR_LEN(loop->nodes); */
-}
-
-/* Returns the pos`th ir_node-child *
- * TODO: This method isn`t very efficient ! *
- * Returns NULL if there isnt`t a pos`th ir_node */
-ir_node *get_loop_node (ir_loop *loop, int pos) {
- int child_nr, node_nr = -1;
-
- assert(loop && loop->kind == k_ir_loop);
- assert(pos < get_loop_n_nodes(loop));
-
- for (child_nr = 0; child_nr < ARR_LEN(loop->children); child_nr++) {
- if(*(loop -> children[child_nr].kind) == k_ir_node)
- node_nr++;
- if(node_nr == pos)
- return(loop -> children[child_nr].node);
- }
- DDML(loop);
- printf("pos: %d\n", pos);
- assert(0 && "no child at pos found");
- return NULL;
-}
-
-/* Use EXCLUSIVELY this function to add nodes, otherwise the loop->n_nodes
- is invalid! */
-
-static INLINE void
-add_loop_node(ir_loop *loop, ir_node *n) {
- loop_element ln;
- ln.node = n;
- assert(loop && loop->kind == k_ir_loop);
- assert(get_kind(n) == k_ir_node);
- ARR_APP1 (loop_element, loop->children, ln);
- loop->n_nodes++;
-}
-
-/** Returns the number of elements contained in loop. */
-int get_loop_n_elements (ir_loop *loop) {
- assert(loop && loop->kind == k_ir_loop);
- return(ARR_LEN(loop->children));
-}
-
-/*
- Returns the pos`th loop element.
- This may be a loop_node or a ir_node. The caller of this function has
- to check the *(loop_element.kind) field for "k_ir_node" or "k_ir_loop"
- and then select the apropriate "loop_element.node" or "loop_element.son".
-*/
-
-loop_element get_loop_element (ir_loop *loop, int pos) {
- assert(loop && loop->kind == k_ir_loop && pos < ARR_LEN(loop->children));
-
- return(loop -> children[pos]);
-}
-
-int get_loop_element_pos(ir_loop *loop, void *le) {
- int i;
- assert(loop && loop->kind == k_ir_loop);
-
- for (i = 0; i < get_loop_n_elements(loop); i++)
- if (get_loop_element(loop, i).node == le) return i;
- return -1;
-}
-
-int get_loop_loop_nr(ir_loop *loop) {
- assert(loop && loop->kind == k_ir_loop);
-#ifdef DEBUG_libfirm
- return loop->loop_nr;
-#else
- return (int)loop;
-#endif
-}
-
-
-/** A field to connect additional information to a loop. Only valid
- if libfirm_debug is set. */
-void set_loop_link (ir_loop *loop, void *link) {
- assert(loop && loop->kind == k_ir_loop);
-#ifdef DEBUG_libfirm
- loop->link = link;
-#endif
-}
-void *get_loop_link (const ir_loop *loop) {
- assert(loop && loop->kind == k_ir_loop);
-#ifdef DEBUG_libfirm
- return loop->link;
-#else
- return NULL;
-#endif
-}
+static ir_loop *new_loop(void)
+{
+ ir_loop *father = current_loop;
+ ir_loop *son = alloc_loop(father, get_irg_obstack(outermost_ir_graph));
-/* The outermost loop is remarked in the surrounding graph. */
-void set_irg_loop(ir_graph *irg, ir_loop *loop) {
- assert(irg);
- irg->loop = loop;
+ current_loop = son;
+ return father;
}
-ir_loop *get_irg_loop(ir_graph *irg) {
- assert(irg);
- return irg->loop;
-}
-
/**********************************************************************/
/* Constructing and destructing the loop/backedge information. **/
/* Initialization steps. **********************************************/
-static INLINE void
-init_node (ir_node *n, void *env) {
- set_irn_link (n, new_scc_info());
- clear_backedges(n);
-#if 0
- /* Also init nodes not visible in intraproc_view. */
- /* @@@ init_node is called for too many nodes -- this wastes memory!.
- The mem is not lost as its on the obstack. */
- if (intern_get_irn_op(n) == op_Filter) {
- for (i = 0; i < get_Filter_n_cg_preds(n); i++)
- init_node(get_Filter_cg_pred(n, i), NULL);
- }
- if (intern_get_irn_op(n) == op_Block) {
- for (i = 0; i < get_Block_cg_n_cfgpreds(n); i++) {
- init_node(get_Block_cg_cfgpred(n, i), NULL);
- }
- }
- /* The following pattern matches only after a call from above pattern. */
- if ((intern_get_irn_op(n) == op_Proj) /*&& (get_Proj_proj(n) == 0)*/) {
- /* @@@ init_node is called for every proj -- this wastes memory!.
- The mem is not lost as its on the obstack. */
- ir_node *cb = get_Proj_pred(n);
- if ((intern_get_irn_op(cb) == op_CallBegin) ||
- (intern_get_irn_op(cb) == op_EndReg) ||
- (intern_get_irn_op(cb) == op_EndExcept)) {
- init_node(cb, NULL);
- init_node(get_nodes_Block(cb), NULL);
- }
- }
-#endif
-}
-
-static INLINE void
-init_scc_common (void) {
- current_dfn = 1;
- loop_node_cnt = 0;
- if (!node_loop_map) node_loop_map = pmap_create();
- init_stack();
+static inline void init_node(ir_node *n, void *env)
+{
+ struct obstack *obst = (struct obstack*) env;
+ set_irn_link(n, new_scc_info(obst));
+ clear_backedges(n);
}
-static INLINE void
-init_scc (ir_graph *irg) {
- init_scc_common();
- irg_walk_graph (irg, init_node, NULL, NULL);
- /*
- irg_walk (irg, link_to_reg_end, NULL, NULL);
- */
+static inline void init_scc_common(void)
+{
+ current_dfn = 1;
+ loop_node_cnt = 0;
+ init_stack();
}
-static INLINE void
-init_ip_scc (void) {
- init_scc_common();
- cg_walk (init_node, NULL, NULL);
-
-#if EXPERIMENTAL_LOOP_TREE
- cg_walk (link_to_reg_end, NULL, NULL);
-#endif
+static inline void init_scc(ir_graph *irg, struct obstack *obst)
+{
+ init_scc_common();
+ irg_walk_graph(irg, init_node, NULL, obst);
}
-/* Condition for breaking the recursion. */
-static bool is_outermost_Start(ir_node *n) {
- /* Test whether this is the outermost Start node. If so
- recursion must end. */
- if ((intern_get_irn_op(n) == op_Block) &&
- (get_Block_n_cfgpreds(n) == 1) &&
- (intern_get_irn_op(skip_Proj(get_Block_cfgpred(n, 0))) == op_Start) &&
- (get_nodes_Block(skip_Proj(get_Block_cfgpred(n, 0))) == n)) {
- return true;
- }
-#if 0
- /* @@@ Bad condition:
- not possible in interprocedural view as outermost_graph is
- not necessarily the only with a dead-end start block.
- Besides current_ir_graph is not set properly. */
- if ((intern_get_irn_op(n) == op_Block) &&
- (n == get_irg_start_block(current_ir_graph))) {
- if ((!interprocedural_view) ||
- (current_ir_graph == outermost_ir_graph))
- return true;
- }
-#endif
- return false;
+static inline void finish_scc(void)
+{
+ finish_stack();
+}
+
+/**
+ * Check whether a given node represents the outermost Start
+ * block. In intra-procedural view this is the start block of the
+ * current graph, in interprocedural view it is the start block
+ * of the outer most graph.
+ *
+ * @param n the node to check
+ *
+ * This is the condition for breaking the scc recursion.
+ */
+static int is_outermost_Start(ir_node *n)
+{
+ /* Test whether this is the outermost Start node. */
+ if (is_Block(n) && get_Block_n_cfgpreds(n) == 1) {
+ ir_node *pred = skip_Proj(get_Block_cfgpred(n, 0));
+ if (is_Start(pred) && get_nodes_block(pred) == n)
+ return 1;
+ }
+ return 0;
}
/* When to walk from nodes to blocks. Only for Control flow operations? */
-static INLINE int
-get_start_index(ir_node *n) {
-#undef BLOCK_BEFORE_NODE
-#define BLOCK_BEFORE_NODE 1
-
-#if BLOCK_BEFORE_NODE
-
- /* This version assures, that all nodes are ordered absolutely. This allows
- to undef all nodes in the heap analysis if the block is false, which means
- not reachable.
- I.e., with this code, the order on the loop tree is correct. But a (single)
- test showed the loop tree is deeper. */
- if (intern_get_irn_op(n) == op_Phi ||
- intern_get_irn_op(n) == op_Block ||
- (intern_get_irn_op(n) == op_Filter && interprocedural_view) ||
- (get_irg_pinned(get_irn_irg(n)) == floats &&
- get_op_pinned(get_irn_op(n)) == floats))
- // Here we could test for backedge at -1 which is illegal
- return 0;
- else
- return -1;
-
-#else
-
- /* This version causes deeper loop trees (at least we verified this
- for Polymor).
- But it guarantees that Blocks are analysed before nodes contained in the
- block. If so, we can set the value to undef if the block is not \
- executed. */
- if (is_cfop(n) || is_fragile_op(n) || intern_get_irn_op(n) == op_Start)
- return -1;
- else
- return 0;
-
-#endif
+static inline int get_start_index(ir_node *n)
+{
+ /* This version assures, that all nodes are ordered absolutely. This allows
+ to undef all nodes in the heap analysis if the block is false, which
+ means not reachable.
+ I.e., with this code, the order on the loop tree is correct. But a
+ (single) test showed the loop tree is deeper. */
+ if (is_Phi(n) ||
+ is_Block(n) ||
+ (get_irg_pinned(get_irn_irg(n)) == op_pin_state_floats &&
+ get_irn_pinned(n) == op_pin_state_floats))
+ // Here we could test for backedge at -1 which is illegal
+ return 0;
+ else
+ return -1;
+}
+
+/**
+ * Return non-zero if the given node is a legal loop header:
+ * Block, Phi
+ *
+ * @param n the node to check
+ */
+static inline int is_possible_loop_head(ir_node *n)
+{
+ return is_Block(n) || is_Phi(n);
}
+/**
+ * Returns non-zero if n is a loop header, i.e., it is a Block or Phi
+ * node and has predecessors within the loop and out of the loop.
+ *
+ * @param n the node to check
+ * @param root only needed for assertion.
+ */
+static int is_head(ir_node *n, ir_node *root)
+{
+ int i, arity;
+ int some_outof_loop = 0, some_in_loop = 0;
-#if 0
-/* Returns current_ir_graph and set it to the irg of predecessor index
- of node n. */
-static INLINE ir_graph *
-switch_irg (ir_node *n, int index) {
- ir_graph *old_current = current_ir_graph;
-
- if (interprocedural_view) {
- /* Only Filter and Block nodes can have predecessors in other graphs. */
- if (intern_get_irn_op(n) == op_Filter)
- n = get_nodes_Block(n);
- if (intern_get_irn_op(n) == op_Block) {
- ir_node *cfop = skip_Proj(get_Block_cfgpred(n, index));
- if (is_ip_cfop(cfop)) {
- current_ir_graph = get_irn_irg(cfop);
- set_irg_visited(current_ir_graph, get_max_irg_visited());
- }
- }
- }
-
- return old_current;
-}
+ /* Test for legal loop header: Block, Phi, ... */
+ if (!is_possible_loop_head(n))
+ return 0;
-/* Walks up the stack passing n and then finding the node
- where we walked into the irg n is contained in.
- Here we switch the irg. */
-static ir_graph *
-find_irg_on_stack (ir_node *n) {
- ir_node *m;
- ir_graph *old_current = current_ir_graph;
- int i;
-
- if (interprocedural_view) {
- for (i = tos; i >= 0; i--) {
- if (stack[i] == n) break;
- }
- if (i < 0) i = tos;
-
- assert (i >= 0);
- for (; i >= 0; i--) {
- m = stack[i];
- /*printf(" Visiting %d ", i); DDMN(m);*/
- if (is_ip_cfop(m)) {
- current_ir_graph = get_irn_irg(m);
- break;
- }
- if (intern_get_irn_op(m) == op_Filter) {
- /* Find the corresponding ip_cfop */
- ir_node *pred = stack[i+1];
- int j;
- for (j = 0; j < get_Filter_n_cg_preds(m); j++)
- if (get_Filter_cg_pred(m, j) == pred) break;
- if (j >= get_Filter_n_cg_preds(m))
- /* It is a filter we didn't pass as the predecessors are marked. */
- continue;
- assert(get_Filter_cg_pred(m, j) == pred);
- switch_irg(m, j);
- break;
- }
- }
- }
-
- return old_current;
-}
+ if (!is_outermost_Start(n)) {
+#ifndef NDEBUG
+ int uplink = get_irn_uplink(root);
+#else
+ (void) root;
#endif
+ arity = get_irn_arity(n);
+ for (i = get_start_index(n); i < arity; i++) {
+ ir_node *pred;
+ if (is_backedge(n, i))
+ continue;
+ pred = get_irn_n(n, i);
+ if (! irn_is_in_stack(pred)) {
+ some_outof_loop = 1;
+ } else {
+ assert(get_irn_uplink(pred) >= uplink);
+ some_in_loop = 1;
+ }
+ }
+ }
+ return some_outof_loop & some_in_loop;
+}
-#if 0
-static void test(ir_node *pred, ir_node *root, ir_node *this) {
- int i;
- if (get_irn_uplink(pred) >= get_irn_uplink(root)) return;
-
- printf("this: %d ", get_irn_uplink(this)); DDMN(this);
- printf("pred: %d ", get_irn_uplink(pred)); DDMN(pred);
- printf("root: %d ", get_irn_uplink(root)); DDMN(root);
+/**
+ * Returns non-zero if n is possible loop head of an endless loop.
+ * I.e., it is a Block or Phi node and has only predecessors
+ * within the loop.
+ *
+ * @param n the node to check
+ * @param root only needed for assertion.
+ */
+static int is_endless_head(ir_node *n, ir_node *root)
+{
+ int i, arity;
+ int none_outof_loop = 1, some_in_loop = 0;
- printf("tos: %d\n", tos);
+ /* Test for legal loop header: Block, Phi, ... */
+ if (!is_possible_loop_head(n))
+ return 0;
- for (i = tos; i >= 0; i--) {
- ir_node *n = stack[i];
- if (!n) continue;
- printf(" uplink: %d, pos: %d ", get_irn_uplink(n), i); DDMN(n);
- }
-}
+ if (!is_outermost_Start(n)) {
+#ifndef NDEBUG
+ int uplink = get_irn_uplink(root);
+#else
+ (void) root;
#endif
-
-/* Test for legal loop header: Block, Phi, ... */
-INLINE static bool is_possible_loop_head(ir_node *n) {
- ir_op *op = intern_get_irn_op(n);
- return ((op == op_Block) ||
- (op == op_Phi) ||
- ((op == op_Filter) && interprocedural_view));
+ arity = get_irn_arity(n);
+ for (i = get_start_index(n); i < arity; i++) {
+ ir_node *pred;
+ if (is_backedge(n, i))
+ continue;
+ pred = get_irn_n(n, i);
+ if (!irn_is_in_stack(pred)) {
+ none_outof_loop = 0;
+ } else {
+ assert(get_irn_uplink(pred) >= uplink);
+ some_in_loop = 1;
+ }
+ }
+ }
+ return none_outof_loop & some_in_loop;
}
-/* Returns true if n is a loop header, i.e., it is a Block, Phi
- or Filter node and has predecessors within the loop and out
- of the loop.
- @arg root: only needed for assertion. */
-static bool
-is_head (ir_node *n, ir_node *root)
+/** Returns index of the predecessor with the smallest dfn number
+ greater-equal than limit. */
+static int smallest_dfn_pred(ir_node *n, int limit)
{
- int i, arity;
- int some_outof_loop = 0, some_in_loop = 0;
-
- /* Test for legal loop header: Block, Phi, ... */
- if (!is_possible_loop_head(n))
- return false;
-
- if (!is_outermost_Start(n)) {
- arity = intern_get_irn_arity(n);
- for (i = get_start_index(n); i < arity; i++) {
- ir_node *pred = intern_get_irn_n(n, i);
- assert(pred);
- if (is_backedge(n, i)) continue;
- if (!irn_is_in_stack(pred)) {
- some_outof_loop = 1;
- } else {
- if(get_irn_uplink(pred) < get_irn_uplink(root))
- {
- DDMN(pred); DDMN(root);
- }
- assert(get_irn_uplink(pred) >= get_irn_uplink(root));
- some_in_loop = 1;
- }
- }
- }
- return some_outof_loop && some_in_loop;
+ int i, index = -2, min = -1;
+
+ if (!is_outermost_Start(n)) {
+ int arity = get_irn_arity(n);
+ for (i = get_start_index(n); i < arity; i++) {
+ ir_node *pred = get_irn_n(n, i);
+ if (is_backedge(n, i) || !irn_is_in_stack(pred))
+ continue;
+ if (get_irn_dfn(pred) >= limit && (min == -1 || get_irn_dfn(pred) < min)) {
+ index = i;
+ min = get_irn_dfn(pred);
+ }
+ }
+ }
+ return index;
}
-/* Returns index of the predecessor with the smallest dfn number
- greater-equal than limit. */
-static int
-smallest_dfn_pred (ir_node *n, int limit)
+/**
+ * Returns index of the predecessor with the largest dfn number.
+ */
+static int largest_dfn_pred(ir_node *n)
{
- int i, index = -2, min = -1;
-
- if (!is_outermost_Start(n)) {
- int arity = intern_get_irn_arity(n);
- for (i = get_start_index(n); i < arity; i++) {
- ir_node *pred = intern_get_irn_n(n, i);
- assert(pred);
- if (is_backedge(n, i) || !irn_is_in_stack(pred)) continue;
- if (get_irn_dfn(pred) >= limit && (min == -1 || get_irn_dfn(pred) < min)) {
- index = i;
- min = get_irn_dfn(pred);
- }
- }
- }
- return index;
+ int i, index = -2, max = -1;
+
+ if (!is_outermost_Start(n)) {
+ int arity = get_irn_arity(n);
+ for (i = get_start_index(n); i < arity; i++) {
+ ir_node *pred = get_irn_n(n, i);
+ if (is_backedge (n, i) || !irn_is_in_stack(pred))
+ continue;
+ if (get_irn_dfn(pred) > max) {
+ index = i;
+ max = get_irn_dfn(pred);
+ }
+ }
+ }
+ return index;
}
-/* Returns index of the predecessor with the largest dfn number. */
-static int
-largest_dfn_pred (ir_node *n)
+/**
+ * Searches the stack for possible loop heads. Tests these for backedges.
+ * If it finds a head with an unmarked backedge it marks this edge and
+ * returns the tail of the loop.
+ * If it finds no backedge returns NULL.
+ * ("disable_backedge" in fiasco)
+ *
+ * @param n A node where uplink == dfn.
+ */
+static ir_node *find_tail(ir_node *n)
{
- int i, index = -2, max = -1;
-
- if (!is_outermost_Start(n)) {
- int arity = intern_get_irn_arity(n);
- for (i = get_start_index(n); i < arity; i++) {
- ir_node *pred = intern_get_irn_n(n, i);
- if (is_backedge (n, i) || !irn_is_in_stack(pred)) continue;
- if (get_irn_dfn(pred) > max) {
- index = i;
- max = get_irn_dfn(pred);
- }
- }
- }
- return index;
-}
-
-/* Searches the stack for possible loop heads. Tests these for backedges.
- If it finds a head with an unmarked backedge it marks this edge and
- returns the tail of the loop.
- If it finds no backedge returns NULL.
- ("disable_backedge" in fiasco) */
-
-static ir_node *
-find_tail (ir_node *n) {
- ir_node *m;
- int i, res_index = -2;
-
- /*
- if (!icfg && rm_cyclic_phis && remove_cyclic_phis (n)) return NULL;
- */
-
- m = stack[tos-1]; /* tos = top of stack */
- if (is_head (m, n)) {
- res_index = smallest_dfn_pred(m, 0);
- if ((res_index == -2) && /* no smallest dfn pred found. */
- (n == m))
- return NULL;
- } else {
- if (m == n) return NULL;
- for (i = tos-2; ; --i) {
- m = stack[i];
- if (is_head (m, n)) {
- res_index = smallest_dfn_pred (m, get_irn_dfn(m) + 1);
- if (res_index == -2) /* no smallest dfn pred found. */
- res_index = largest_dfn_pred (m);
- break;
- }
- }
- }
- assert (res_index > -2);
-
- set_backedge (m, res_index);
- return is_outermost_Start(n) ? NULL : intern_get_irn_n(m, res_index);
-}
-
-
-#if EXPERIMENTAL_LOOP_TREE
-
-/* ----------------------------------------------------------------
- AS: This is experimantal code to build loop trees suitable for
- the heap analysis. Does not work correctly right now... :-(
-
+ ir_node *m;
+ int i, res_index = -2;
+
+ m = stack[tos-1]; /* tos = top of stack */
+ if (is_head(m, n)) {
+ res_index = smallest_dfn_pred(m, 0);
+ if ((res_index == -2) && /* no smallest dfn pred found. */
+ (n == m))
+ return NULL;
+ } else {
+ if (m == n) return NULL; // Is this to catch Phi - self loops?
+ for (i = tos-2; i >= 0; --i) {
+ m = stack[i];
+
+ if (is_head(m, n)) {
+ res_index = smallest_dfn_pred(m, get_irn_dfn(m) + 1);
+ if (res_index == -2) /* no smallest dfn pred found. */
+ res_index = largest_dfn_pred(m);
+
+ if ((m == n) && (res_index == -2)) { /* don't walk past loop head. */
+ i = -1;
+ }
+ break;
+ }
+
+ /* We should not walk past our selves on the stack: The upcoming nodes
+ are not in this loop. We assume a loop not reachable from Start. */
+ if (m == n) {
+ i = -1;
+ break;
+ }
+ }
- Search in stack for the corresponding first Call-End-ProjX that
- corresponds to one of the control flow predecessors of the given
- block, that is the possible callers.
- returns: the control predecessor to chose\
- or -1 if no corresponding Call-End-Node could be found
- on the stack.
- - -------------------------------------------------------------- */
+ if (i < 0) {
+ /* A dead loop not reachable from Start. */
+ for (i = tos-2; i >= 0; --i) {
+ m = stack[i];
+ if (is_endless_head(m, n)) {
+ res_index = smallest_dfn_pred(m, get_irn_dfn(m) + 1);
+ if (res_index == -2) /* no smallest dfn pred found. */
+ res_index = largest_dfn_pred (m);
+ break;
+ }
+ /* It's not an unreachable loop, either. */
+ if (m == n)
+ break;
+ }
+ //assert(0 && "no head found on stack");
+ }
-int search_endproj_in_stack(ir_node *start_block)
-{
- int i, j;
- assert(is_Block(start_block));
- for(i = tos - 1; i >= 0; --i)
- {
- DDMN(stack[i]);
- if(get_irn_op(stack[i]) == op_Proj && get_irn_mode(stack[i]) == mode_X &&
- get_irn_op(get_irn_n(stack[i], 0)) == op_EndReg)
- {
- printf("FOUND PROJ!!!!!!!!!!!!!!!!!!!!!!!!!!\n");
- ir_node *end_projx = stack[i];
-
- for(j = 0; j < get_irn_arity(start_block); j++)
- {
- ir_node *begin_projx = get_Block_cfgpred(get_irg_start_block(get_irn_irg(end_projx)), get_Proj_proj(end_projx));
- DDMN(begin_projx);
- if(get_irn_n(start_block, j) == begin_projx)
- {
- printf("FOUND IT!!!!!!!!!!!!!!!!!!\n");
- return(j);
+ }
+ if (res_index <= -2) {
+ /* It's a completely bad loop: without Phi/Block nodes that can
+ be a head. I.e., the code is "dying". We break the loop by
+ setting Bad nodes. */
+ ir_graph *irg = get_irn_irg(n);
+ ir_mode *mode = get_irn_mode(n);
+ ir_node *bad = new_r_Bad(irg, mode);
+ int arity = get_irn_arity(n);
+ for (i = -1; i < arity; ++i) {
+ set_irn_n(n, i, bad);
}
- }
+ return NULL;
}
- }
- return(-1);
-}
-
+ assert(res_index > -2);
-static pmap *projx_link = NULL;
-
-void link_to_reg_end (ir_node *n, void *env) {
- if(get_irn_op(n) == op_Proj && get_irn_mode(n) == mode_X && get_irn_op(get_irn_n(n, 0)) == op_EndReg)
- {
- /* Reg End Projx -> Find the CallBegin Projx and hash it */
- ir_node *end_projx = n;
- ir_node *begin_projx = get_Block_cfgpred(get_irg_start_block(get_irn_irg(end_projx)), get_Proj_proj(end_projx));
- printf("Linked the following ProjxNodes:\n");
- DDMN(begin_projx);
- DDMN(end_projx);
- set_projx_link(begin_projx, end_projx);
- }
+ set_backedge(m, res_index);
+ return is_outermost_Start(n) ? NULL : get_irn_n(m, res_index);
}
-void set_projx_link(ir_node *cb_projx, ir_node *end_projx)
+static inline int is_outermost_loop(ir_loop *l)
{
- if(projx_link == NULL)
- projx_link = pmap_create();
- pmap_insert(projx_link, (void *)cb_projx, (void *)end_projx);
+ return l == get_loop_outer_loop(l);
}
-ir_node *get_projx_link(ir_node *cb_projx)
-{
- return((ir_node *) pmap_get(projx_link, (void *)cb_projx));
-}
-
-#endif
-
-
-
-/*************************************************************
+/*-----------------------------------------------------------*
* The core algorithm. *
- *************************************************************/
-
-
-static void scc (ir_node *n) {
- int i, *visited;
- if (irn_visited(n)) return;
- mark_irn_visited(n);
-
- /* Initialize the node */
- set_irn_dfn(n, current_dfn); /* Depth first number for this node */
- set_irn_uplink(n, current_dfn); /* ... is default uplink. */
- set_irn_loop(n, NULL);
- current_dfn ++;
- push(n);
-
- /* AS: get_start_index might return -1 for Control Flow Nodes, and thus a negative
- array index would be passed to is_backedge(). But CFG Nodes dont't have a backedge array,
- so is_backedge does not access array[-1] but correctly returns false! */
-
- if (!is_outermost_Start(n)) {
- int arity = intern_get_irn_arity(n);
-
-#if EXPERIMENTAL_LOOP_TREE
-
- /* This is meant to be used with the experimenatl code above.
- If the above code is not used any more, this can be deleted, too.... */
-
- if(interprocedural_view &&
- is_Block(n) &&
- get_irn_op(get_irn_n(n, 0)) == op_Proj &&
- get_irn_op(get_irn_n(get_irn_n(n, 0), 0)) == op_CallBegin)
- {
- /* We are at the start node of a function:
- Walk to the callers in the correct order! */
- DDMN(n);
- DDMN(get_irn_n(get_irn_n(n, 0), 0));
- for(i = 0; i < arity; i++)
- {
- int pred_nr;
- ir_node *m;
-
- pred_nr = search_endproj_in_stack(n);
- assert(pred_nr >= 0);
- if(is_backedge(n, pred_nr))
- continue;
- m = get_irn_n(n, pred_nr);
- scc(m);
-
- if (irn_is_in_stack(m)) {
- /* Uplink of m is smaller if n->m is a backedge.
- Propagate the uplink to mark the loop. */
- if (get_irn_uplink(m) < get_irn_uplink(n))
- set_irn_uplink(n, get_irn_uplink(m));
- }
- }
- }
- else
+ *-----------------------------------------------------------*/
-#endif
-
- {
- for (i = get_start_index(n); i < arity; i++) {
- ir_node *m;
- if (is_backedge(n, i)) continue;
- /* printf("i: %d\n", i); */
- m = intern_get_irn_n(n, i); /* get_irn_ip_pred(n, i); */
- /* if ((!m) || (intern_get_irn_op(m) == op_Unknown)) continue; */
- scc (m);
- if (irn_is_in_stack(m)) {
- /* Uplink of m is smaller if n->m is a backedge.
- Propagate the uplink to mark the loop. */
- if (get_irn_uplink(m) < get_irn_uplink(n))
- set_irn_uplink(n, get_irn_uplink(m));
- }
+/**
+ * The core algorithm: Find strongly coupled components.
+ *
+ * @param n node to start
+ */
+static void scc(ir_node *n)
+{
+ if (irn_visited_else_mark(n))
+ return;
+
+ /* Initialize the node */
+ set_irn_dfn(n, current_dfn); /* Depth first number for this node */
+ set_irn_uplink(n, current_dfn); /* ... is default uplink. */
+ set_irn_loop(n, NULL);
+ ++current_dfn;
+ push(n);
+
+ /* AS: get_start_index might return -1 for Control Flow Nodes, and thus a negative
+ array index would be passed to is_backedge(). But CFG Nodes dont't have a backedge array,
+ so is_backedge does not access array[-1] but correctly returns false! */
+
+ if (!is_outermost_Start(n)) {
+ int i, arity = get_irn_arity(n);
+
+ for (i = get_start_index(n); i < arity; ++i) {
+ ir_node *m;
+ if (is_backedge(n, i))
+ continue;
+ m = get_irn_n(n, i);
+ scc(m);
+ if (irn_is_in_stack(m)) {
+ /* Uplink of m is smaller if n->m is a backedge.
+ Propagate the uplink to mark the loop. */
+ if (get_irn_uplink(m) < get_irn_uplink(n))
+ set_irn_uplink(n, get_irn_uplink(m));
+ }
+ }
}
- }
- }
-
- if (get_irn_dfn(n) == get_irn_uplink(n)) {
- /* This condition holds for
- 1) the node with the incoming backedge.
- That is: We found a loop!
- 2) Straight line code, because no uplink has been propagated, so the
- uplink still is the same as the dfn.
-
- But n might not be a proper loop head for the analysis. Proper loop
- heads are Block and Phi nodes. find_tail searches the stack for
- Block's and Phi's and takes those nodes as loop heads for the current
- loop instead and marks the incoming edge as backedge. */
-
- ir_node *tail = find_tail(n);
- if (tail) {
- /* We have a loop, that is no straight line code,
- because we found a loop head!
- Next actions: Open a new loop on the loop tree and
- try to find inner loops */
-
-
-#define NO_LOOPS_WITHOUT_HEAD 1
-#if NO_LOOPS_WITHOUT_HEAD
-
- /* This is an adaption of the algorithm from fiasco / optscc to
- * avoid loops without Block or Phi as first node. This should
- * severely reduce the number of evaluations of nodes to detect
- * a fixpoint in the heap analysis.
- * Further it avoids loops without firm nodes that cause errors
- * in the heap analyses. */
-
- ir_loop *l;
- int close;
- if (get_loop_n_elements(current_loop) > 0) {
- l = new_loop();
- close = 1;
- } else {
- l = current_loop;
- close = 0;
- }
-#else
-
- ir_loop *l = new_loop();
+ if (get_irn_dfn(n) == get_irn_uplink(n)) {
+ /* This condition holds for
+ 1) the node with the incoming backedge.
+ That is: We found a loop!
+ 2) Straight line code, because no uplink has been propagated, so the
+ uplink still is the same as the dfn.
+
+ But n might not be a proper loop head for the analysis. Proper loop
+ heads are Block and Phi nodes. find_tail() searches the stack for
+ Block's and Phi's and takes those nodes as loop heads for the current
+ loop instead and marks the incoming edge as backedge. */
+
+ ir_node *tail = find_tail(n);
+ if (tail != NULL) {
+ /* We have a loop, that is no straight line code,
+ because we found a loop head!
+ Next actions: Open a new loop on the loop tree and
+ try to find inner loops */
+
+ /* This is an adaption of the algorithm from fiasco / optscc to
+ * avoid loops without Block or Phi as first node. This should
+ * severely reduce the number of evaluations of nodes to detect
+ * a fixpoint in the heap analysis.
+ * Further it avoids loops without firm nodes that cause errors
+ * in the heap analyses.
+ * But attention: don't do it for the outermost loop: This loop
+ * is not iterated. A first block can be a loop head in case of
+ * an endless recursion. */
+
+ ir_loop *l;
+ int close;
+ if ((get_loop_n_elements(current_loop) > 0) || (is_outermost_loop(current_loop))) {
+ l = new_loop();
+ close = 1;
+ } else {
+ l = current_loop;
+ close = 0;
+ }
+
+ /* Remove the loop from the stack ... */
+ pop_scc_unmark_visit(n);
+
+ /* The current backedge has been marked, that is temporarily eliminated,
+ by find tail. Start the scc algorithm
+ again on the subgraph that is left (the current loop without the backedge)
+ in order to find more inner loops. */
+ scc(tail);
+
+ assert(irn_visited(n));
+ if (close)
+ close_loop(l);
+ } else {
+ /* No loop head was found, that is we have straight line code.
+ Pop all nodes from the stack to the current loop. */
+ pop_scc_to_loop(n);
+ }
+ }
+}
-#endif
+void construct_backedges(ir_graph *irg)
+{
+ ir_graph *rem = current_ir_graph;
+ ir_loop *head_rem;
+ struct obstack temp;
- /* Remove the loop from the stack ... */
- pop_scc_unmark_visit (n);
+ current_ir_graph = irg;
+ outermost_ir_graph = irg;
- /* GL @@@ remove experimental stuff rem = find_irg_on_stack(tail); */
+ obstack_init(&temp);
+ init_scc(irg, &temp);
- /* The current backedge has been marked, that is temporarily eliminated,
- by find tail. Start the scc algorithm
- anew on the subgraph thats left (the current loop without the backedge)
- in order to find more inner loops. */
+ current_loop = NULL;
+ new_loop(); /* sets current_loop */
+ head_rem = current_loop; /* Just for assertion */
- scc (tail);
+ inc_irg_visited(irg);
- /* GL @@@ remove experimental stuff current_ir_graph = rem; */
+ scc(get_irg_end(irg));
- assert (irn_visited(n));
-#if NO_LOOPS_WITHOUT_HEAD
- if (close)
-#endif
- close_loop(l);
- }
- else
- {
- /* AS: No loop head was found, that is we have straightline code.
- Pop all nodes from the stack to the current loop. */
- pop_scc_to_loop(n);
- }
- }
-}
+ finish_scc();
+ obstack_free(&temp, NULL);
-/* Constructs backedge information for irg. In interprocedural view constructs
- backedges for all methods called by irg, too. */
-void construct_backedges(ir_graph *irg) {
- ir_graph *rem = current_ir_graph;
- ir_loop *head_rem;
-
- assert(!interprocedural_view &&
- "not implemented, use construct_ip_backedges");
-
- current_ir_graph = irg;
- outermost_ir_graph = irg;
-
- init_scc(current_ir_graph);
-
- current_loop = NULL;
- new_loop(); /* sets current_loop */
- head_rem = current_loop; /* Just for assertion */
-
- if (interprocedural_view) {
- set_irg_visited(current_ir_graph, inc_max_irg_visited());
- init_ip_walk ();
- } else {
- inc_irg_visited(current_ir_graph);
- }
-
- scc(get_irg_end(current_ir_graph));
-
- if (interprocedural_view) finish_ip_walk();
-
- assert(head_rem == current_loop);
- set_irg_loop(current_ir_graph, current_loop);
- set_irg_loopinfo_state(current_ir_graph, loopinfo_consistent);
- assert(get_irg_loop(current_ir_graph)->kind == k_ir_loop);
- /*
- irg->loops = current_loop;
- if (icfg == 1) {
- int count = 0;
- int depth = 0;
- count_loop (the_loop, &count, &depth);
- }
- }
- */
- current_ir_graph = rem;
+ assert(head_rem == current_loop);
+ mature_loops(current_loop, get_irg_obstack(irg));
+ set_irg_loop(irg, current_loop);
+ add_irg_properties(irg, IR_GRAPH_PROPERTY_CONSISTENT_LOOPINFO);
+ assert(get_irg_loop(irg)->kind == k_ir_loop);
+ current_ir_graph = rem;
}
-
-#if 0
-void construct_ip_backedges (void) {
- ir_graph *rem = current_ir_graph;
- int rem_ipv = interprocedural_view;
- int i, j;
-
- outermost_ir_graph = get_irp_main_irg();
-
- init_ip_scc();
-
- current_loop = NULL;
- new_loop(); /* sets current_loop */
- interprocedural_view = 1;
-
- inc_max_irg_visited();
- for (i = 0; i < get_irp_n_irgs(); i++)
- set_irg_visited(get_irp_irg(i), get_max_irg_visited());
-
- for (i = 0; i < get_irp_n_irgs(); i++) {
- ir_node *sb;
- current_ir_graph = get_irp_irg(i);
- /* Find real entry points */
- sb = get_irg_start_block(current_ir_graph);
- if ((get_Block_n_cfgpreds(sb) > 1) ||
- (get_nodes_Block(get_Block_cfgpred(sb, 0)) != sb)) continue;
- /* Compute scc for this graph */
- outermost_ir_graph = current_ir_graph;
- set_irg_visited(outermost_ir_graph, get_max_irg_visited());
- scc(get_irg_end(current_ir_graph));
- for (j = 0; j < get_End_n_keepalives(get_irg_end(outermost_ir_graph)); j++)
- scc(get_End_keepalive(get_irg_end(outermost_ir_graph), j));
- }
-
- set_irg_loop(outermost_ir_graph, current_loop);
- set_irg_loopinfo_state(current_ir_graph, loopinfo_ip_consistent);
- assert(get_irg_loop(outermost_ir_graph)->kind == k_ir_loop);
-
- current_ir_graph = rem;
- interprocedural_view = rem_ipv;
-}
-#else
-void construct_ip_backedges (void) {
- ir_graph *rem = current_ir_graph;
- int rem_ipv = interprocedural_view;
- int i;
-
- outermost_ir_graph = get_irp_main_irg();
-
- init_ip_scc();
-
- current_loop = NULL;
- new_loop(); /* sets current_loop */
- interprocedural_view = 1;
-
- inc_max_irg_visited();
- for (i = 0; i < get_irp_n_irgs(); i++)
- set_irg_visited(get_irp_irg(i), get_max_irg_visited());
-
- /** We have to start the walk at the same nodes as cg_walk. **/
- /* Walk starting at unreachable procedures. Only these
- * have End blocks visible in interprocedural view. */
- for (i = 0; i < get_irp_n_irgs(); i++) {
- ir_node *sb;
- current_ir_graph = get_irp_irg(i);
-
- sb = get_irg_start_block(current_ir_graph);
-
- if ((get_Block_n_cfgpreds(sb) > 1) ||
- (get_nodes_block(get_Block_cfgpred(sb, 0)) != sb)) continue;
-
- scc(get_irg_end(current_ir_graph));
- }
-
- /* Check whether we walked all procedures: there could be procedures
- with cyclic calls but no call from the outside. */
- for (i = 0; i < get_irp_n_irgs(); i++) {
- ir_node *sb;
- current_ir_graph = get_irp_irg(i);
-
- /* Test start block: if inner procedure end and end block are not
- * visible and therefore not marked. */
- sb = get_irg_start_block(current_ir_graph);
- if (get_irn_visited(sb) < get_irg_visited(current_ir_graph)) scc(sb);
- }
-
- /* Walk all endless loops in inner procedures.
- * We recognize an inner procedure if the End node is not visited. */
- for (i = 0; i < get_irp_n_irgs(); i++) {
- ir_node *e;
- current_ir_graph = get_irp_irg(i);
-
- e = get_irg_end(current_ir_graph);
- if (get_irn_visited(e) < get_irg_visited(current_ir_graph)) {
- int j;
- /* Don't visit the End node. */
- for (j = 0; j < get_End_n_keepalives(e); j++) scc(get_End_keepalive(e, j));
- }
- }
-
- set_irg_loop(outermost_ir_graph, current_loop);
- set_irg_loopinfo_state(current_ir_graph, loopinfo_ip_consistent);
- assert(get_irg_loop(outermost_ir_graph)->kind == k_ir_loop);
-
- current_ir_graph = rem;
- interprocedural_view = rem_ipv;
-}
-#endif
-
-static void reset_backedges(ir_node *n) {
- if (is_possible_loop_head(n)) {
- int rem = interprocedural_view;
- interprocedural_view = 1;
- clear_backedges(n);
- interprocedural_view = 0;
- clear_backedges(n);
- interprocedural_view = rem;
- }
+static void reset_backedges(ir_node *n)
+{
+ if (is_possible_loop_head(n)) {
+ clear_backedges(n);
+ }
}
-static void loop_reset_backedges(ir_loop *l) {
- int i;
- reset_backedges(get_loop_node(l, 0));
- for (i = 0; i < get_loop_n_nodes(l); ++i)
- set_irn_loop(get_loop_node(l, i), NULL);
- for (i = 0; i < get_loop_n_sons(l); ++i) {
- loop_reset_backedges(get_loop_son(l, i));
- }
+static void loop_reset_node(ir_node *n, void *env)
+{
+ (void) env;
+ set_irn_loop(n, NULL);
+ reset_backedges(n);
}
-/** Removes all loop information.
- Resets all backedges */
-void free_loop_information(ir_graph *irg) {
- if (get_irg_loop(irg))
- loop_reset_backedges(get_irg_loop(irg));
- set_irg_loop(irg, NULL);
- set_irg_loopinfo_state(current_ir_graph, loopinfo_none);
- /* We cannot free the loop nodes, they are on the obstack. */
+void free_loop_information(ir_graph *irg)
+{
+ irg_walk_graph(irg, loop_reset_node, NULL, NULL);
+ set_irg_loop(irg, NULL);
+ clear_irg_properties(current_ir_graph, IR_GRAPH_PROPERTY_CONSISTENT_LOOPINFO);
+ /* We cannot free the loop nodes, they are on the obstack. */
}
-
-void free_all_loop_information (void) {
- int i;
- int rem = interprocedural_view;
- interprocedural_view = 1; /* To visit all filter nodes */
- for (i = 0; i < get_irp_n_irgs(); i++) {
- free_loop_information(get_irp_irg(i));
- }
- pmap_destroy(node_loop_map);
- node_loop_map = NULL;
- interprocedural_view = rem;
+void free_all_loop_information(void)
+{
+ size_t i;
+ for (i = 0; i < get_irp_n_irgs(); i++) {
+ free_loop_information(get_irp_irg(i));
+ }
}
+/* ------------------------------------------------------------------- */
+/* Simple analyses based on the loop information */
+/* ------------------------------------------------------------------- */
+static int is_loop_variant(ir_loop *l, ir_loop *b)
+{
+ size_t i, n_elems;
+ if (l == b) return 1;
+ n_elems = get_loop_n_elements(l);
+ for (i = 0; i < n_elems; ++i) {
+ loop_element e = get_loop_element(l, i);
+ if (is_ir_loop(e.kind))
+ if (is_loop_variant(e.son, b))
+ return 1;
+ }
-/* Debug stuff *************************************************/
-
-static int test_loop_node(ir_loop *l) {
- int i, has_node = 0, found_problem = 0;
- loop_element le;
-
- assert(l && l->kind == k_ir_loop);
-
- if (get_loop_n_elements(l) == 0) {
- printf(" Loop completely empty! "); DDML(l);
- found_problem = 1;
- dump_loop(l, "-ha");
- }
-
- le = get_loop_element(l, 0);
- if (*(le.kind) != k_ir_node) {
- assert(le.kind && *(le.kind) == k_ir_loop);
- printf(" First loop element is not a node! "); DDML(l);
- printf(" "); DDML(le.son);
-
- found_problem = 1;
- dump_loop(l, "-ha");
- }
-
- if ((*(le.kind) == k_ir_node) && !is_possible_loop_head(le.node)) {
- printf(" Wrong node as head! "); DDML(l);
- printf(" "); DDMN(le.node);
- found_problem = 1;
- dump_loop(l, "-ha");
- }
-
- if ((get_loop_depth(l) != 0) &&
- (*(le.kind) == k_ir_node) && !has_backedges(le.node)) {
- printf(" Loop head has no backedges! "); DDML(l);
- printf(" "); DDMN(le.node);
- found_problem = 1;
- dump_loop(l, "-ha");
- }
-
- /* Recur */
- has_node = 0;
- for (i = 0; i < get_loop_n_elements(l); ++i) {
- le = get_loop_element(l, i);
- if (*(le.kind) == k_ir_node)
- has_node++;
- else
- if (test_loop_node(le.son)) found_problem = 1;
- }
-
- if (has_node == 0) {
- printf(" Loop has no firm node! "); DDML(l);
- found_problem = 1;
- dump_loop(l, "-ha");
- }
-
- if (get_loop_loop_nr(l) == 11819)
- dump_loop(l, "-ha-debug");
-
- return found_problem;
+ return 0;
}
-/** Prints all loop nodes that
- * - do not have any firm nodes, only loop sons
- * - the header is not a Phi, Block or Filter.
- */
-void find_strange_loop_nodes(ir_loop *l) {
- int found_problem = 0;
- printf("\nTesting loop "); DDML(l);
- found_problem = test_loop_node(l);
- printf("Finished Test\n\n");
- if (found_problem) exit(0);
-
+int is_loop_invariant(const ir_node *n, const ir_node *block)
+{
+ ir_loop *l = get_irn_loop(block);
+ const ir_node *b = is_Block(n) ? n : get_nodes_block(n);
+ return !is_loop_variant(l, get_irn_loop(b));
}
projects / libfirm / blobdiff