X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=ir%2Fana%2Firloop.h;h=21e96a8917899f3f8c15da236f376e9038d92e31;hb=5afaf595a454bb6b87899b317f2ae99ed03bf62e;hp=63b36b53f50633ddcfc64ca766830595e9a3cd69;hpb=fd4953d44b540a94242b66672e99aa12b0c377ff;p=libfirm diff --git a/ir/ana/irloop.h b/ir/ana/irloop.h index 63b36b53f..21e96a891 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. * @@ -39,8 +37,11 @@ * 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. */ +int is_inter_backedge(ir_node *n, int pos); +int is_intra_backedge(ir_node *n, int pos); bool is_backedge (ir_node *n, int pos); /** Remarks that edge pos is a backedge. */ void set_backedge (ir_node *n, int pos); @@ -51,6 +52,7 @@ bool has_backedges (ir_node *n); /** Sets backedge information to zero. */ void clear_backedges (ir_node *n); +/* ------------------------------------------------------------------- */ /** * The loops datastructure. * @@ -67,16 +69,22 @@ 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. */ +/* ------------------------------------------------------------------- */ typedef struct ir_loop ir_loop; -/* 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. NULL if node is in no loop. */ @@ -90,9 +98,16 @@ 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. */ @@ -106,7 +121,8 @@ loop_element get_loop_element (ir_loop *loop, int pos); int get_loop_element_pos(ir_loop *loop, void *le); /** Returns a unique node number for the loop node to make output - readable. Casten pointer if libfirm_debug not set. */ + 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 @@ -114,28 +130,84 @@ int get_loop_loop_nr(ir_loop *loop); void set_loop_link (ir_loop *loop, void *link); void *get_loop_link (const ir_loop *loop); -/* - * Constructing and destructing the loop/backedge information. - */ +/* ------------------------------------------------------------------- */ +/* Constructing and destructing the loop/backedge information. */ +/* ------------------------------------------------------------------- */ -/** Constructs backedge information for irg in intraprocedural view. */ +/** 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. + * + * @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); -/** 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); +/** 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 loop tree only for control flow. */ -void construct_cf_backedges(ir_graph *irg); -void construct_ip_cf_backedges (void); +/** 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 true, 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_ */