diff options
Diffstat (limited to 'gcc/flow.c')
| -rw-r--r-- | gcc/flow.c | 28 |
1 files changed, 27 insertions, 1 deletions
@@ -482,6 +482,7 @@ static void flow_loops_tree_build PARAMS ((struct loops *)); static int flow_loop_level_compute PARAMS ((struct loop *, int)); static int flow_loops_level_compute PARAMS ((struct loops *)); static void delete_dead_jumptables PARAMS ((void)); +static bool back_edge_of_syntactic_loop_p PARAMS ((basic_block, basic_block)); /* Find basic blocks of the current function. F is the first insn of the function and NREGS the number of register @@ -1968,6 +1969,30 @@ redirect_edge_and_branch_force (e, target) return new_bb; } +/* Helper function for split_edge. Return true in case edge BB2 to BB1 + is back edge of syntactic loop. */ +static bool +back_edge_of_syntactic_loop_p (bb1, bb2) + basic_block bb1, bb2; +{ + rtx insn; + int count; + if (bb1->index > bb2->index) + return false; + if (bb1->index == bb2->index) + return true; + for (insn = bb1->end; insn != bb2->head && count >= 0; + insn = NEXT_INSN (insn)) + if (GET_CODE (insn) == NOTE) + { + if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG) + count++; + if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_END) + count--; + } + return count >= 0; +} + /* Split a (typically critical) edge. Return the new block. Abort on abnormal edges. @@ -2115,7 +2140,8 @@ split_edge (edge_in) if (old_succ != EXIT_BLOCK_PTR && PREV_INSN (old_succ->head) && GET_CODE (PREV_INSN (old_succ->head)) == NOTE - && NOTE_LINE_NUMBER (PREV_INSN (old_succ->head)) == NOTE_INSN_LOOP_BEG) + && NOTE_LINE_NUMBER (PREV_INSN (old_succ->head)) == NOTE_INSN_LOOP_BEG + && !back_edge_of_syntactic_loop_p (old_succ, old_pred)) bb_note = emit_note_before (NOTE_INSN_BASIC_BLOCK, PREV_INSN (old_succ->head)); else if (old_succ != EXIT_BLOCK_PTR) |