diff options
Diffstat (limited to 'gcc/reorg.c')
-rw-r--r-- | gcc/reorg.c | 39 |
1 files changed, 31 insertions, 8 deletions
diff --git a/gcc/reorg.c b/gcc/reorg.c index dd50d21..89442e3 100644 --- a/gcc/reorg.c +++ b/gcc/reorg.c @@ -2494,22 +2494,25 @@ fill_simple_delay_slots (int non_jumps_p) #endif } -/* Follow any unconditional jump at LABEL; +/* Follow any unconditional jump at LABEL, for the purpose of redirecting JUMP; return the ultimate label reached by any such chain of jumps. Return a suitable return rtx if the chain ultimately leads to a return instruction. If LABEL is not followed by a jump, return LABEL. If the chain loops or we can't find end, return LABEL, - since that tells caller to avoid changing the insn. */ + since that tells caller to avoid changing the insn. + If the returned label is obtained by following a REG_CROSSING_JUMP + jump, set *CROSSING to true, otherwise set it to false. */ static rtx -follow_jumps (rtx label) +follow_jumps (rtx label, rtx jump, bool *crossing) { rtx insn; rtx next; rtx value = label; int depth; + *crossing = false; if (ANY_RETURN_P (label)) return label; for (depth = 0; @@ -2537,6 +2540,11 @@ follow_jumps (rtx label) || GET_CODE (PATTERN (tem)) == ADDR_DIFF_VEC)) break; + if (!targetm.can_follow_jump (jump, insn)) + break; + if (!*crossing) + *crossing + = find_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX) != NULL_RTX; value = this_label; } if (depth == 10) @@ -2984,6 +2992,7 @@ fill_slots_from_thread (rtx insn, rtx condition, rtx thread, if (new_thread != thread) { rtx label; + bool crossing = false; gcc_assert (thread_if_true); @@ -2991,7 +3000,7 @@ fill_slots_from_thread (rtx insn, rtx condition, rtx thread, && redirect_with_delay_list_safe_p (insn, JUMP_LABEL (new_thread), delay_list)) - new_thread = follow_jumps (JUMP_LABEL (new_thread)); + new_thread = follow_jumps (JUMP_LABEL (new_thread), insn, &crossing); if (ANY_RETURN_P (new_thread)) label = find_end_label (new_thread); @@ -3001,7 +3010,11 @@ fill_slots_from_thread (rtx insn, rtx condition, rtx thread, label = get_label_before (new_thread); if (label) - reorg_redirect_jump (insn, label); + { + reorg_redirect_jump (insn, label); + if (crossing) + set_unique_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX); + } } return delay_list; @@ -3347,6 +3360,7 @@ relax_delay_slots (rtx first) for (insn = first; insn; insn = next) { rtx other; + bool crossing; next = next_active_insn (insn); @@ -3357,7 +3371,9 @@ relax_delay_slots (rtx first) && (condjump_p (insn) || condjump_in_parallel_p (insn)) && !ANY_RETURN_P (target_label = JUMP_LABEL (insn))) { - target_label = skip_consecutive_labels (follow_jumps (target_label)); + target_label + = skip_consecutive_labels (follow_jumps (target_label, insn, + &crossing)); if (ANY_RETURN_P (target_label)) target_label = find_end_label (target_label); @@ -3369,7 +3385,11 @@ relax_delay_slots (rtx first) } if (target_label && target_label != JUMP_LABEL (insn)) - reorg_redirect_jump (insn, target_label); + { + reorg_redirect_jump (insn, target_label); + if (crossing) + set_unique_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX); + } /* See if this jump conditionally branches around an unconditional jump. If so, invert this jump and point it to the target of the @@ -3503,7 +3523,8 @@ relax_delay_slots (rtx first) /* If this jump goes to another unconditional jump, thread it, but don't convert a jump into a RETURN here. */ - trial = skip_consecutive_labels (follow_jumps (target_label)); + trial = skip_consecutive_labels (follow_jumps (target_label, delay_insn, + &crossing)); if (ANY_RETURN_P (trial)) trial = find_end_label (trial); @@ -3512,6 +3533,8 @@ relax_delay_slots (rtx first) { reorg_redirect_jump (delay_insn, trial); target_label = trial; + if (crossing) + set_unique_reg_note (insn, REG_CROSSING_JUMP, NULL_RTX); } /* If the first insn at TARGET_LABEL is redundant with a previous |