diff options
Diffstat (limited to 'gcc/flow.c')
| -rw-r--r-- | gcc/flow.c | 127 |
1 files changed, 68 insertions, 59 deletions
diff --git a/gcc/flow.c b/gcc/flow.c index 1bea9c2959f..a8573e1642a 100644 --- a/gcc/flow.c +++ b/gcc/flow.c @@ -253,6 +253,7 @@ varray_type basic_block_for_insn; bit of surgery to be able to use or co-opt the routines in jump. */ static rtx label_value_list; +static rtx tail_recursion_label_list; /* Holds information for tracking conditional register life information. */ struct reg_cond_life_info @@ -307,7 +308,7 @@ struct propagate_block_info /* Forward declarations */ static int count_basic_blocks PARAMS ((rtx)); -static rtx find_basic_blocks_1 PARAMS ((rtx)); +static void find_basic_blocks_1 PARAMS ((rtx)); static void clear_edges PARAMS ((void)); static void make_edges PARAMS ((rtx)); static void make_label_edge PARAMS ((sbitmap *, basic_block, @@ -325,6 +326,7 @@ static void delete_eh_regions PARAMS ((void)); static int can_delete_note_p PARAMS ((rtx)); static void expunge_block PARAMS ((basic_block)); static int can_delete_label_p PARAMS ((rtx)); +static int tail_recursion_label_p PARAMS ((rtx)); static int merge_blocks_move_predecessor_nojumps PARAMS ((basic_block, basic_block)); static int merge_blocks_move_successor_nojumps PARAMS ((basic_block, @@ -437,7 +439,7 @@ find_basic_blocks (f, nregs, file) VARRAY_BB_INIT (basic_block_info, n_basic_blocks, "basic_block_info"); - label_value_list = find_basic_blocks_1 (f); + find_basic_blocks_1 (f); /* Record the block to which an insn belongs. */ /* ??? This should be done another way, by which (perhaps) a label is @@ -535,7 +537,7 @@ count_basic_blocks (f) Collect and return a list of labels whose addresses are taken. This will be used in make_edges for use with computed gotos. */ -static rtx +static void find_basic_blocks_1 (f) rtx f; { @@ -543,7 +545,8 @@ find_basic_blocks_1 (f) int i = 0; rtx bb_note = NULL_RTX; rtx eh_list = NULL_RTX; - rtx label_value_list = NULL_RTX; + rtx lvl = NULL_RTX; + rtx trll = NULL_RTX; rtx head = NULL_RTX; rtx end = NULL_RTX; @@ -667,6 +670,12 @@ find_basic_blocks_1 (f) int region = (note ? INTVAL (XEXP (note, 0)) : 1); int call_has_abnormal_edge = 0; + /* If this is a call placeholder, record its tail recursion + label, if any. */ + if (GET_CODE (PATTERN (insn)) == CALL_PLACEHOLDER + && XEXP (PATTERN (insn), 3) != NULL_RTX) + trll = alloc_EXPR_LIST (0, XEXP (PATTERN (insn), 3), trll); + /* If there is an EH region or rethrow, we have an edge. */ if ((eh_list && region > 0) || find_reg_note (insn, REG_EH_RETHROW, NULL_RTX)) @@ -724,15 +733,16 @@ find_basic_blocks_1 (f) rtx lab = XEXP (note, 0), next; if (lab == eh_return_stub_label) - ; + ; else if ((next = next_nonnote_insn (lab)) != NULL && GET_CODE (next) == JUMP_INSN && (GET_CODE (PATTERN (next)) == ADDR_VEC || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC)) ; + else if (GET_CODE (lab) == NOTE) + ; else - label_value_list - = alloc_EXPR_LIST (0, XEXP (note, 0), label_value_list); + lvl = alloc_EXPR_LIST (0, XEXP (note, 0), lvl); } } } @@ -745,7 +755,8 @@ find_basic_blocks_1 (f) if (i != n_basic_blocks) abort (); - return label_value_list; + label_value_list = lvl; + tail_recursion_label_list = trll; } /* Tidy the CFG by deleting unreachable code and whatnot. */ @@ -761,7 +772,8 @@ cleanup_cfg (f) mark_critical_edges (); /* Kill the data we won't maintain. */ - label_value_list = NULL_RTX; + free_EXPR_LIST_list (&label_value_list); + free_EXPR_LIST_list (&tail_recursion_label_list); } /* Create a new basic block consisting of the instructions between @@ -1853,8 +1865,14 @@ flow_delete_insn_chain (start, finish) next = NEXT_INSN (start); if (GET_CODE (start) == NOTE && !can_delete_note_p (start)) ; - else if (GET_CODE (start) == CODE_LABEL && !can_delete_label_p (start)) - ; + else if (GET_CODE (start) == CODE_LABEL + && ! can_delete_label_p (start)) + { + const char *name = LABEL_NAME (start); + PUT_CODE (start, NOTE); + NOTE_LINE_NUMBER (start) = NOTE_INSN_DELETED_LABEL; + NOTE_SOURCE_FILE (start) = name; + } else next = flow_delete_insn (start); @@ -1910,20 +1928,6 @@ flow_delete_block (b) } prev = &XEXP (x, 1); } - - /* This label may be referenced by code solely for its value, or - referenced by static data, or something. We have determined - that it is not reachable, but cannot delete the label itself. - Save code space and continue to delete the balance of the block, - along with properly updating the cfg. */ - if (!can_delete_label_p (insn)) - { - /* If we've only got one of these, skip the whole deleting - insns thing. */ - if (insn == b->end) - goto no_delete_insns; - insn = NEXT_INSN (insn); - } } /* Include any jump table following the basic block. */ @@ -1944,8 +1948,6 @@ flow_delete_block (b) /* Selectively delete the entire chain. */ flow_delete_insn_chain (insn, end); - no_delete_insns: - /* Remove the edges into and out of this block. Note that there may indeed be edges in, if we are removing an unreachable loop. */ { @@ -2063,6 +2065,19 @@ can_delete_label_p (label) return 1; } +static int +tail_recursion_label_p (label) + rtx label; +{ + rtx x; + + for (x = tail_recursion_label_list; x ; x = XEXP (x, 1)) + if (label == XEXP (x, 0)) + return 1; + + return 0; +} + /* Blocks A and B are to be merged into a single block A. The insns are already contiguous, hence `nomove'. */ @@ -2180,19 +2195,10 @@ merge_blocks_move_predecessor_nojumps (a, b) start = a->head; end = a->end; - /* We want to delete the BARRIER after the end of the insns we are - going to move. If we don't find a BARRIER, then do nothing. This - can happen in some cases if we have labels we can not delete. - - Similarly, do nothing if we can not delete the label at the start - of the target block. */ barrier = next_nonnote_insn (end); - if (GET_CODE (barrier) != BARRIER - || (GET_CODE (b->head) == CODE_LABEL - && ! can_delete_label_p (b->head))) - return 0; - else - flow_delete_insn (barrier); + if (GET_CODE (barrier) != BARRIER) + abort (); + flow_delete_insn (barrier); /* Move block and loop notes out of the chain so that we do not disturb their order. @@ -2240,20 +2246,23 @@ merge_blocks_move_successor_nojumps (a, b) start = b->head; end = b->end; + barrier = NEXT_INSN (end); - /* We want to delete the BARRIER after the end of the insns we are - going to move. If we don't find a BARRIER, then do nothing. This - can happen in some cases if we have labels we can not delete. + /* Recognize a jump table following block B. */ + if (GET_CODE (barrier) == CODE_LABEL + && NEXT_INSN (barrier) + && GET_CODE (NEXT_INSN (barrier)) == JUMP_INSN + && (GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_VEC + || GET_CODE (PATTERN (NEXT_INSN (barrier))) == ADDR_DIFF_VEC)) + { + end = NEXT_INSN (barrier); + barrier = NEXT_INSN (end); + } - Similarly, do nothing if we can not delete the label at the start - of the target block. */ - barrier = next_nonnote_insn (end); - if (GET_CODE (barrier) != BARRIER - || (GET_CODE (b->head) == CODE_LABEL - && ! can_delete_label_p (b->head))) - return 0; - else - flow_delete_insn (barrier); + /* There had better have been a barrier there. Delete it. */ + if (GET_CODE (barrier) != BARRIER) + abort (); + flow_delete_insn (barrier); /* Move block and loop notes out of the chain so that we do not disturb their order. @@ -2287,17 +2296,17 @@ merge_blocks (e, b, c) edge e; basic_block b, c; { + /* If C has a tail recursion label, do not merge. There is no + edge recorded from the call_placeholder back to this label, as + that would make optimize_sibling_and_tail_recursive_calls more + complex for no gain. */ + if (GET_CODE (c->head) == CODE_LABEL + && tail_recursion_label_p (c->head)) + return 0; + /* If B has a fallthru edge to C, no need to move anything. */ if (e->flags & EDGE_FALLTHRU) { - /* If a label still appears somewhere and we cannot delete the label, - then we cannot merge the blocks. The edge was tidied already. */ - - rtx insn, stop = NEXT_INSN (c->head); - for (insn = NEXT_INSN (b->end); insn != stop; insn = NEXT_INSN (insn)) - if (GET_CODE (insn) == CODE_LABEL && !can_delete_label_p (insn)) - return 0; - merge_blocks_nomove (b, c); if (rtl_dump_file) |
