diff options
| -rw-r--r-- | gcc/ChangeLog | 8 | ||||
| -rw-r--r-- | gcc/basic-block.h | 4 | ||||
| -rw-r--r-- | gcc/flow.c | 196 |
3 files changed, 115 insertions, 93 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 5b691069f51..04b20048c2e 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,11 @@ +2000-04-07 Richard Henderson <rth@cygnus.com> + + * basic-block.h (merge_blocks_nomove): Declare. + (tidy_fallthru_edge): Declare. + * flow.c (merge_blocks_nomove): Document as merging into previous + blocks. Remove cruft from between blocks; remove all edges out of A. + (tidy_fallthru_edge): Export. + 2000-04-06 Alex Samuel <samuel@codesourcery.com> * ssa.c (compute_conservative_reg_partition): Declare with diff --git a/gcc/basic-block.h b/gcc/basic-block.h index 5fa62268b01..e59c16e6a76 100644 --- a/gcc/basic-block.h +++ b/gcc/basic-block.h @@ -231,7 +231,9 @@ extern void make_edge PARAMS ((sbitmap *, basic_block, basic_block, int)); extern void remove_edge PARAMS ((edge)); extern void create_basic_block PARAMS ((int, rtx, rtx, rtx)); - +extern void merge_blocks_nomove PARAMS ((basic_block, basic_block)); +extern void tidy_fallthru_edge PARAMS ((edge, basic_block, + basic_block)); /* Structure to hold information for each natural loop. */ struct loop diff --git a/gcc/flow.c b/gcc/flow.c index dc50d178b88..4dc9624b7d2 100644 --- a/gcc/flow.c +++ b/gcc/flow.c @@ -302,10 +302,8 @@ static int merge_blocks_move_predecessor_nojumps PARAMS ((basic_block, basic_block)); static int merge_blocks_move_successor_nojumps PARAMS ((basic_block, basic_block)); -static void merge_blocks_nomove PARAMS ((basic_block, basic_block)); static int merge_blocks PARAMS ((edge,basic_block,basic_block)); static void try_merge_blocks PARAMS ((void)); -static void tidy_fallthru_edge PARAMS ((edge,basic_block,basic_block)); static void tidy_fallthru_edges PARAMS ((void)); static int verify_wide_reg_1 PARAMS ((rtx *, void *)); static void verify_wide_reg PARAMS ((int, rtx, rtx)); @@ -2032,6 +2030,109 @@ can_delete_label_p (label) return 1; } +/* Blocks A and B are to be merged into a single block A. The insns + are already contiguous, hence `nomove'. */ + +void +merge_blocks_nomove (a, b) + basic_block a, b; +{ + edge e; + rtx b_head, b_end, a_end; + rtx del_first = NULL_RTX, del_last = NULL_RTX; + int b_empty = 0; + + /* If there was a CODE_LABEL beginning B, delete it. */ + b_head = b->head; + b_end = b->end; + if (GET_CODE (b_head) == CODE_LABEL) + { + /* Detect basic blocks with nothing but a label. This can happen + in particular at the end of a function. */ + if (b_head == b_end) + b_empty = 1; + del_first = del_last = b_head; + b_head = NEXT_INSN (b_head); + } + + /* Delete the basic block note. */ + if (GET_CODE (b_head) == NOTE + && NOTE_LINE_NUMBER (b_head) == NOTE_INSN_BASIC_BLOCK) + { + if (b_head == b_end) + b_empty = 1; + if (! del_last) + del_first = b_head; + del_last = b_head; + b_head = NEXT_INSN (b_head); + } + + /* If there was a jump out of A, delete it. */ + a_end = a->end; + if (GET_CODE (a_end) == JUMP_INSN) + { + rtx prev; + + prev = prev_nonnote_insn (a_end); + if (!prev) + prev = a->head; + + del_first = a_end; + +#ifdef HAVE_cc0 + /* If this was a conditional jump, we need to also delete + the insn that set cc0. */ + if (prev && sets_cc0_p (prev)) + { + rtx tmp = prev; + prev = prev_nonnote_insn (prev); + if (!prev) + prev = a->head; + del_first = tmp; + } +#endif + + a_end = prev; + } + + /* Delete everything marked above as well as crap that might be + hanging out between the two blocks. */ + flow_delete_insn_chain (del_first, del_last); + + /* Normally there should only be one successor of A and that is B, but + partway though the merge of blocks for conditional_execution we'll + be merging a TEST block with THEN and ELSE successors. Free the + whole lot of them and hope the caller knows what they're doing. */ + while (a->succ) + remove_edge (a->succ); + + /* Adjust the edges out of B for the new owner. */ + for (e = b->succ; e ; e = e->succ_next) + e->src = a; + a->succ = b->succ; + + /* B hasn't quite yet ceased to exist. Attempt to prevent mishap. */ + b->pred = b->succ = NULL; + + /* Reassociate the insns of B with A. */ + if (!b_empty) + { + if (basic_block_for_insn) + { + BLOCK_FOR_INSN (b_head) = a; + while (b_head != b_end) + { + b_head = NEXT_INSN (b_head); + BLOCK_FOR_INSN (b_head) = a; + } + } + a_end = b_end; + } + a->end = a_end; + + expunge_block (b); +} + /* Blocks A and B are to be merged into a single block. A has no incoming fallthru edge, so it can be moved before B without adding or modifying any jumps (aside from the jump from A to B). */ @@ -2145,95 +2246,6 @@ merge_blocks_move_successor_nojumps (a, b) return 1; } -/* Blocks A and B are to be merged into a single block. The insns - are already contiguous, hence `nomove'. */ - -static void -merge_blocks_nomove (a, b) - basic_block a, b; -{ - edge e; - rtx b_head, b_end, a_end; - int b_empty = 0; - - /* If there was a CODE_LABEL beginning B, delete it. */ - b_head = b->head; - b_end = b->end; - if (GET_CODE (b_head) == CODE_LABEL) - { - /* Detect basic blocks with nothing but a label. This can happen - in particular at the end of a function. */ - if (b_head == b_end) - b_empty = 1; - b_head = flow_delete_insn (b_head); - } - - /* Delete the basic block note. */ - if (GET_CODE (b_head) == NOTE - && NOTE_LINE_NUMBER (b_head) == NOTE_INSN_BASIC_BLOCK) - { - if (b_head == b_end) - b_empty = 1; - b_head = flow_delete_insn (b_head); - } - - /* If there was a jump out of A, delete it. */ - a_end = a->end; - if (GET_CODE (a_end) == JUMP_INSN) - { - rtx prev; - - prev = prev_nonnote_insn (a_end); - if (!prev) - prev = a->head; - -#ifdef HAVE_cc0 - /* If this was a conditional jump, we need to also delete - the insn that set cc0. */ - - if (prev && sets_cc0_p (prev)) - { - rtx tmp = prev; - prev = prev_nonnote_insn (prev); - if (!prev) - prev = a->head; - flow_delete_insn (tmp); - } -#endif - - /* Note that a->head != a->end, since we should have at least a - bb note plus the jump, so prev != insn. */ - flow_delete_insn (a_end); - a_end = prev; - } - - /* By definition, there should only be one successor of A, and that is - B. Free that edge struct. */ - n_edges--; - free (a->succ); - - /* Adjust the edges out of B for the new owner. */ - for (e = b->succ; e ; e = e->succ_next) - e->src = a; - a->succ = b->succ; - - /* Reassociate the insns of B with A. */ - if (!b_empty) - { - BLOCK_FOR_INSN (b_head) = a; - while (b_head != b_end) - { - b_head = NEXT_INSN (b_head); - BLOCK_FOR_INSN (b_head) = a; - } - a_end = b_head; - } - a->end = a_end; - - /* Compact the basic block array. */ - expunge_block (b); -} - /* Attempt to merge basic blocks that are potentially non-adjacent. Return true iff the attempt succeeded. */ @@ -2366,7 +2378,7 @@ try_merge_blocks () /* The given edge should potentially be a fallthru edge. If that is in fact true, delete the jump and barriers that are in the way. */ -static void +void tidy_fallthru_edge (e, b, c) edge e; basic_block b, c; |
