diff options
| -rw-r--r-- | gcc/ChangeLog | 12 | ||||
| -rw-r--r-- | gcc/basic-block.h | 2 | ||||
| -rw-r--r-- | gcc/flow.c | 84 |
3 files changed, 98 insertions, 0 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index b3f6bcdf0d8..2dc37e85446 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,15 @@ +Tue Sep 21 14:51:23 EDT 1999 Andrew MacLeod <amacleod@cygnus.com> + + * flow.c (remove_edge): New function to remove an edge from the + flow graph. + (remove_fake_successors): New function to remove fake successor edges. + (remove_fake_edges): New function to remove all fake edges from the + flow graph. + (add_fake_exit_edges): New function to add fake edges from all blocks + with no successors to the exit block. + * basic-block.h (remove_fake_edges, add_fake_exit_edges): Add + prototypes for new functions. + Tue Sep 21 14:49:53 EDT 1999 Andrew MacLeod <amacleod@cygnus.com> * config/mips/elf64.h (ASM_OUTPUT_CONSTRUCTOR, ASM_OUTPUT_DESTRUCTOR): diff --git a/gcc/basic-block.h b/gcc/basic-block.h index 06ef7cf452c..26b509cccf7 100644 --- a/gcc/basic-block.h +++ b/gcc/basic-block.h @@ -244,6 +244,8 @@ extern void free_basic_block_vars PROTO ((int)); extern basic_block split_edge PROTO ((edge)); extern void insert_insn_on_edge PROTO ((rtx, edge)); extern void commit_edge_insertions PROTO ((void)); +extern void remove_fake_edges PROTO ((void)); +extern void add_fake_exit_edges PROTO ((void)); /* This structure maintains an edge list vector. */ struct edge_list diff --git a/gcc/flow.c b/gcc/flow.c index 95743d882eb..d47612b5d6b 100644 --- a/gcc/flow.c +++ b/gcc/flow.c @@ -6751,3 +6751,87 @@ find_edge_index (edge_list, pred, succ) return (EDGE_INDEX_NO_EDGE); } +/* This function will remove an edge from the flow graph. */ +static void +remove_edge (e) + edge e; +{ + edge last_pred = NULL; + edge last_succ = NULL; + edge tmp; + basic_block src, dest; + src = e->src; + dest = e->dest; + for (tmp = src->succ; tmp && tmp != e; tmp = tmp->succ_next) + last_succ = tmp; + + if (!tmp) + abort (); + if (last_succ) + last_succ->succ_next = e->succ_next; + else + src->succ = e->succ_next; + + for (tmp = dest->pred; tmp && tmp != e; tmp = tmp->pred_next) + last_pred = tmp; + + if (!tmp) + abort (); + if (last_pred) + last_pred->pred_next = e->pred_next; + else + dest->pred = e->pred_next; + + free (e); + +} + +/* This routine will remove any fake successor edges for a basic block. + When the edge is removed, it is also removed from whatever predecessor + list it is in. */ +static void +remove_fake_successors (bb) + basic_block bb; +{ + edge e; + for (e = bb->succ; e ; ) + { + edge tmp = e; + e = e->succ_next; + if ((tmp->flags & EDGE_FAKE) == EDGE_FAKE) + remove_edge (tmp); + } +} + +/* This routine will remove all fake edges from the flow graph. If + we remove all fake successors, it will automatically remove all + fake predecessors. */ +void +remove_fake_edges () +{ + int x; + edge e; + basic_block bb; + + for (x = 0; x < n_basic_blocks; x++) + { + edge tmp, last = NULL; + bb = BASIC_BLOCK (x); + remove_fake_successors (bb); + } + /* we've handled all successors except the entry block's. */ + remove_fake_successors (ENTRY_BLOCK_PTR); +} + +/* This functions will add a fake edge between any block which has no + successors, and the exit block. Some data flow equations require these + edges to exist. */ +void +add_fake_exit_edges () +{ + int x; + + for (x = 0; x < n_basic_blocks; x++) + if (BASIC_BLOCK (x)->succ == NULL) + make_edge (BASIC_BLOCK (x), EXIT_BLOCK_PTR, EDGE_FAKE); +} |