diff options
Diffstat (limited to 'gcc/flow.c')
| -rw-r--r-- | gcc/flow.c | 112 |
1 files changed, 93 insertions, 19 deletions
diff --git a/gcc/flow.c b/gcc/flow.c index b46c87ea46a..432a990220a 100644 --- a/gcc/flow.c +++ b/gcc/flow.c @@ -1,5 +1,6 @@ /* Data flow analysis for GNU compiler. - Copyright (C) 1987, 88, 92-98, 1999 Free Software Foundation, Inc. + Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998, + 1999, 2000 Free Software Foundation, Inc. This file is part of GNU CC. @@ -1562,7 +1563,12 @@ delete_unreachable_blocks () check that the edge is not a FALLTHRU edge. */ if ((s = b->succ) != NULL && s->succ_next == NULL - && s->dest == c) + && s->dest == c + /* If the last insn is not a normal conditional jump + (or an unconditional jump), then we can not tidy the + fallthru edge because we can not delete the jump. */ + && GET_CODE (b->end) == JUMP_INSN + && condjump_p (b->end)) tidy_fallthru_edge (s, b, c); } @@ -1578,8 +1584,14 @@ delete_unreachable_blocks () /* A loop because chains of blocks might be combineable. */ while ((s = b->succ) != NULL && s->succ_next == NULL + && (s->flags & EDGE_EH) == 0 && (c = s->dest) != EXIT_BLOCK_PTR && c->pred->pred_next == NULL + /* If the last insn is not a normal conditional jump + (or an unconditional jump), then we can not merge + the blocks because we can not delete the jump. */ + && GET_CODE (b->end) == JUMP_INSN + && condjump_p (b->end) && merge_blocks (s, b, c)) continue; @@ -1670,7 +1682,7 @@ delete_block (b) basic_block b; { int deleted_handler = 0; - rtx insn, end; + rtx insn, end, tmp; /* If the head of this block is a CODE_LABEL, then it might be the label for an exception handler which can't be reached. @@ -1717,11 +1729,21 @@ delete_block (b) } } - /* Selectively unlink the insn chain. Include any BARRIER that may - follow the basic block. */ - end = next_nonnote_insn (b->end); - if (!end || GET_CODE (end) != BARRIER) - end = b->end; + /* Include any jump table following the basic block. */ + end = b->end; + if (GET_CODE (end) == JUMP_INSN + && (tmp = JUMP_LABEL (end)) != NULL_RTX + && (tmp = NEXT_INSN (tmp)) != NULL_RTX + && GET_CODE (tmp) == JUMP_INSN + && (GET_CODE (PATTERN (tmp)) == ADDR_VEC + || GET_CODE (PATTERN (tmp)) == ADDR_DIFF_VEC)) + end = tmp; + + /* Include any barrier that may follow the basic block. */ + tmp = next_nonnote_insn (b->end); + if (tmp && GET_CODE (tmp) == BARRIER) + end = tmp; + delete_insn_chain (insn, end); no_delete_insns: @@ -1785,6 +1807,7 @@ flow_delete_insn (insn) { rtx prev = PREV_INSN (insn); rtx next = NEXT_INSN (insn); + rtx note; PREV_INSN (insn) = NULL_RTX; NEXT_INSN (insn) = NULL_RTX; @@ -1804,6 +1827,10 @@ flow_delete_insn (insn) if (GET_CODE (insn) == JUMP_INSN && JUMP_LABEL (insn)) LABEL_NUSES (JUMP_LABEL (insn))--; + /* Also if deleting an insn that references a label. */ + else if ((note = find_reg_note (insn, REG_LABEL, NULL_RTX)) != NULL_RTX) + LABEL_NUSES (XEXP (note, 0))--; + return next; } @@ -2272,11 +2299,14 @@ mark_regs_live_at_end (set) we end up eliminating it, it will be removed from the live list of each basic block by reload. */ - SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM); + if (! reload_completed || frame_pointer_needed) + { + SET_REGNO_REG_SET (set, FRAME_POINTER_REGNUM); #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM - /* If they are different, also mark the hard frame pointer as live */ - SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM); + /* If they are different, also mark the hard frame pointer as live */ + SET_REGNO_REG_SET (set, HARD_FRAME_POINTER_REGNUM); #endif + } /* Mark all global registers, and all registers used by the epilogue as being live at the end of the function since they may be @@ -2707,6 +2737,39 @@ propagate_block (old, first, last, final, significant, bnum, remove_dead_code) can cause trouble for first or last insn in a basic block. */ if (final && insn_is_dead) { + rtx inote; + /* If the insn referred to a label, note that the label is + now less used. */ + for (inote = REG_NOTES (insn); inote; inote = XEXP (inote, 1)) + { + if (REG_NOTE_KIND (inote) == REG_LABEL) + { + rtx label = XEXP (inote, 0); + rtx next; + LABEL_NUSES (label)--; + + /* If this label was attached to an ADDR_VEC, it's + safe to delete the ADDR_VEC. In fact, it's pretty much + mandatory to delete it, because the ADDR_VEC may + be referencing labels that no longer exist. */ + if (LABEL_NUSES (label) == 0 + && (next = next_nonnote_insn (label)) != NULL + && GET_CODE (next) == JUMP_INSN + && (GET_CODE (PATTERN (next)) == ADDR_VEC + || GET_CODE (PATTERN (next)) == ADDR_DIFF_VEC)) + { + rtx pat = PATTERN (next); + int diff_vec_p = GET_CODE (pat) == ADDR_DIFF_VEC; + int len = XVECLEN (pat, diff_vec_p); + int i; + for (i = 0; i < len; i++) + LABEL_NUSES (XEXP (XVECEXP (pat, diff_vec_p, i), 0))--; + + flow_delete_insn (next); + } + } + } + PUT_CODE (insn, NOTE); NOTE_LINE_NUMBER (insn) = NOTE_INSN_DELETED; NOTE_SOURCE_FILE (insn) = 0; @@ -2957,9 +3020,11 @@ insn_dead_p (x, needed, call_ok, notes) /* Don't delete insns to set global regs. */ if ((regno < FIRST_PSEUDO_REGISTER && global_regs[regno]) /* Make sure insns to set frame pointer aren't deleted. */ - || regno == FRAME_POINTER_REGNUM + || (regno == FRAME_POINTER_REGNUM + && (! reload_completed || frame_pointer_needed)) #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM - || regno == HARD_FRAME_POINTER_REGNUM + || (regno == HARD_FRAME_POINTER_REGNUM + && (! reload_completed || frame_pointer_needed)) #endif #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM /* Make sure insns to set arg pointer are never deleted @@ -3258,6 +3323,9 @@ mark_set_1 (needed, dead, x, insn, significant) invalidate_mems_from_autoinc (insn); if (GET_CODE (reg) == MEM && ! side_effects_p (reg) + /* We do not know the size of a BLKmode store, so we do not track + them for redundant store elimination. */ + && GET_MODE (reg) != BLKmode /* There are no REG_INC notes for SP, so we can't assume we'll see everything that invalidates it. To be safe, don't eliminate any stores though SP; none of them should be redundant anyway. */ @@ -3265,9 +3333,11 @@ mark_set_1 (needed, dead, x, insn, significant) mem_set_list = gen_rtx_EXPR_LIST (VOIDmode, reg, mem_set_list); if (GET_CODE (reg) == REG - && (regno = REGNO (reg), regno != FRAME_POINTER_REGNUM) + && (regno = REGNO (reg), ! (regno == FRAME_POINTER_REGNUM + && (! reload_completed || frame_pointer_needed))) #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM - && regno != HARD_FRAME_POINTER_REGNUM + && ! (regno == HARD_FRAME_POINTER_REGNUM + && (! reload_completed || frame_pointer_needed)) #endif #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno]) @@ -3725,12 +3795,14 @@ mark_used_regs (needed, live, x, final, insn) nothing below can be necessary, so waste no more time. */ if (regno == STACK_POINTER_REGNUM #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM - || regno == HARD_FRAME_POINTER_REGNUM + || (regno == HARD_FRAME_POINTER_REGNUM + && (! reload_completed || frame_pointer_needed)) #endif #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM || (regno == ARG_POINTER_REGNUM && fixed_regs[regno]) #endif - || regno == FRAME_POINTER_REGNUM) + || (regno == FRAME_POINTER_REGNUM + && (! reload_completed || frame_pointer_needed))) { /* If this is a register we are going to try to eliminate, don't mark it live here. If we are successful in @@ -3906,9 +3978,11 @@ mark_used_regs (needed, live, x, final, insn) if ((GET_CODE (testreg) == PARALLEL && GET_MODE (testreg) == BLKmode) || (GET_CODE (testreg) == REG - && (regno = REGNO (testreg), regno != FRAME_POINTER_REGNUM) + && (regno = REGNO (testreg), ! (regno == FRAME_POINTER_REGNUM + && (! reload_completed || frame_pointer_needed))) #if FRAME_POINTER_REGNUM != HARD_FRAME_POINTER_REGNUM - && regno != HARD_FRAME_POINTER_REGNUM + && ! (regno == HARD_FRAME_POINTER_REGNUM + && (! reload_completed || frame_pointer_needed)) #endif #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM && ! (regno == ARG_POINTER_REGNUM && fixed_regs[regno]) |