X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fana%2Firloop.h;h=aa454690451e0270c9712b5741465c54c9d32e83;hb=abd43e7e3bf02b19a0bb9b02c0a33b22ec791922;hp=1dfe236f255462195e17d5b1a00c27c0e6d70dc2;hpb=56a871bc4bfe49ae51c8d16fea662a3b1ab1836e;p=libfirm diff --git a/ir/ana/irloop.h b/ir/ana/irloop.h index 1dfe236f2..aa4546904 100644 --- a/ir/ana/irloop.h +++ b/ir/ana/irloop.h @@ -27,9 +27,7 @@ # include "irgraph.h" # include "irnode.h" - -/* @@@ Interprocedural backedges ... ???? */ - +/* ------------------------------------------------------------------- */ /* * Backedge information. * @@ -39,27 +37,33 @@ * The backedge information can only be used if the graph is not in * phase phase_building. */ - -/** Returns true if the predesessor pos is a backedge. */ -bool is_backedge (ir_node *n, int pos); -/** Remarks that edge pos is a backedge. */ +/* ------------------------------------------------------------------- */ + +/** Returns true if the predecessor pos is a backedge in the interprozeduralem view. */ +int is_inter_backedge(ir_node *n, int pos); +/** Returns true if the predecessor pos is a backedge in the intraprocedural view. */ +int is_intra_backedge(ir_node *n, int pos); +/** Returns non-zero if the predecessor pos is a backedge. */ +int is_backedge (ir_node *n, int pos); +/** Marks edge pos as a backedge. */ void set_backedge (ir_node *n, int pos); -/** Remarks that edge pos is not a backedge. */ +/** Marks edge pos as a non-backedge. */ void set_not_backedge (ir_node *n, int pos); -/** Returns true if n has backedges. */ -bool has_backedges (ir_node *n); -/** Sets backedge information to zero. */ +/** Returns non-zero if n has backedges. */ +int has_backedges (ir_node *n); +/** Clears all backedge information. */ void clear_backedges (ir_node *n); +/* ------------------------------------------------------------------- */ /** - * The loops datastructure. + * The loops data structure. * - * The loops datastructure represents circles in the intermediate + * The loops data structure represents circles in the intermediate * representation. It does not represent loops in the terms of a * source program. - * Each ir_graph can contain one outermost loop datastructure. + * Each ir_graph can contain one outermost loop data structure. * loop is the entry point to the nested loops. - * The loop datastructure contains a field indicating the depth of + * The loop data structure contains a field indicating the depth of * the loop within the nesting. Further it contains a list of the * loops with nesting depth -1. Finally it contains a list of all * nodes in the loop. @@ -67,23 +71,28 @@ void clear_backedges (ir_node *n); * @todo We could add a field pointing from a node to the containing loop, * this would cost a lot of memory, though. */ +/* ------------------------------------------------------------------- */ +#ifndef _IR_LOOP_TYPEDEF_ +#define _IR_LOOP_TYPEDEF_ typedef struct ir_loop ir_loop; +#endif -/* Loop elements are loop nodes and ir nodes */ +/** Loop elements: loop nodes and ir nodes */ typedef union { firm_kind *kind; /**< is either k_ir_node or k_ir_loop */ ir_node *node; /**< Pointer to an ir_node element */ ir_loop *son; /**< Pointer to an ir_loop element */ } loop_element; +int is_ir_loop(const void *thing); + +/** Set the outermost loop in ir graph as basic access to loop tree. */ void set_irg_loop(ir_graph *irg, ir_loop *l); + +/* Returns the root loop info (if exists) for an irg. */ ir_loop *get_irg_loop(ir_graph *irg); -/** Returns the loop n is contained in. - assumes current_ir_graph set properly. */ -/* @@@ @@@ @@@ @@@@ @@@ - current impl is very expensive: O(#nodes in irg). - Is used by heapanal (O(#phi)) --> better impl required. */ +/** Returns the loop n is contained in. NULL if node is in no loop. */ ir_loop *get_irn_loop(ir_node *n); /** Returns outer loop, itself if outermost. */ @@ -94,9 +103,16 @@ int get_loop_depth (ir_loop *loop); /* Sons are the inner loops contained in this loop. */ /** Returns the number of inner loops */ int get_loop_n_sons (ir_loop *loop); + +/** Returns the pos`th son loop (inner loop) of a loop. + Returns NULL if there is not a pos`th loop_node. */ ir_loop *get_loop_son (ir_loop *loop, int pos); + /** Returns the number of nodes contained in loop. */ int get_loop_n_nodes (ir_loop *loop); + +/** Returns the pos`th ir_node of a loop. + Returns NULL if there is not a pos`th ir_node. */ ir_node *get_loop_node (ir_loop *loop, int pos); /** Returns the number of elements contained in loop. */ @@ -105,24 +121,98 @@ int get_loop_n_elements (ir_loop *loop); kind pointer, an ir_node* or an ir_loop*. */ loop_element get_loop_element (ir_loop *loop, int pos); -/* - * Constructing and destructing the loop/backedge information. - */ +/** Returns the element number of the loop son in loop. + * Returns -1 if not found. O(|elements|). */ +int get_loop_element_pos(ir_loop *loop, void *le); -/** Constructs backedge information for irg in intraprocedural view. */ +/** Returns a unique node number for the loop node to make output + readable. If libfirm_debug is not set it returns the loop cast to + int. */ +int get_loop_loop_nr(ir_loop *loop); + +/** A field to connect additional information to a loop. Only valid + if libfirm_debug is set, else returns NULL. */ +void set_loop_link (ir_loop *loop, void *link); +void *get_loop_link (const ir_loop *loop); + +/* ------------------------------------------------------------------- */ +/* Constructing and destructing the loop/backedge information. */ +/* ------------------------------------------------------------------- */ + +/** Constructs backedge information and loop tree for a graph in intraprocedural view. + * + * The algorithm views the program representation as a pure graph. + * It assumes that only block and phi nodes may be loop headers. + * The resulting loop tree is a possible visiting order for dataflow + * analysis. + * + * @returns Maximal depth of loop tree. + * + * @remark + * One assumes, the Phi nodes in a block with a backedge have backedges + * at the same positions as the block. This is not the case, as + * the scc algorithms does not respect the program semantics in this case. + * Take a swap in a loop (t = i; i = j; j = t;) This results in two Phi + * nodes. They form a cycle. Once the scc algorithm deleted one of the + * edges, the cycle is removed. The second Phi node does not get a + * backedge! + */ /* @@@ Well, maybe construct_loop_information or analyze_loops ? */ -void construct_backedges(ir_graph *irg); +int construct_backedges(ir_graph *irg); -/** Constructs backedges for all irgs in interprocedural view. All - loops in the graph will be marked as such, not only realizeable - loops and recursions in the program. E.g., if the same funcion is - called twice, there is a loop between the first function return and - the second call. */ -void construct_ip_backedges(void); +/** Constructs backedges for all irgs in interprocedural view. + * + * @see As construct_backedges(), but for interprocedural view. + * + * @remark + * All loops in the graph will be marked as such, not only + * realizeable loops and recursions in the program. E.g., if the + * same funcion is called twice, there is a loop between the first + * function return and the second call. + * + * @returns Maximal depth of loop tree. +*/ +int construct_ip_backedges(void); + +/** Construct loop tree only for control flow. + * + * This constructs loop information resembling the program structure. + * It is useful for loop optimizations and analyses, as, e.g., finding + * iteration variables or loop invariant code motion. + * + * This algorithm computes only back edge information for Block nodes, not + * for Phi nodes. + * + * @returns Maximal depth of loop tree. */ +int construct_cf_backedges(ir_graph *irg); + +/** Construct interprocedural loop tree for control flow. + * + * @see construct_cf_backedges() and construct_ip_backedges(). + */ +int construct_ip_cf_backedges (void); /** Removes all loop information. - Resets all backedges */ + * Resets all backedges. Works for any construction algorithm. + */ void free_loop_information(ir_graph *irg); void free_all_loop_information (void); + + + +/* ------------------------------------------------------------------- */ +/* Simple analyses based on the loop information */ +/* ------------------------------------------------------------------- */ + +/** Test whether a value is loop invariant. + * + * @param n The node to be tested. + * @param block A block node. + * + * Returns non-zero, if the node n is not changed in the loop block + * belongs to or in inner loops of this block. */ +int is_loop_invariant(ir_node *n, ir_node *block); + + #endif /* _IRLOOP_H_ */