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flow.c (redirect_edge_and_branch): Bail out on complex edges. 

* flow.c (redirect_edge_and_branch): Bail out on complex edges.
	(try_optimize_cfg): Do not remove tail recursive labels before sibcall.
	* jump.c (mark_jump_label): Do not forward branches.

Co-Authored-By: Jan Hubicka <jh@suse.cz>

From-SVN: r44118
This commit is contained in:
Richard Henderson 2001-07-18 10:11:11 -07:00 committed by Jan Hubicka
parent 02d92e3b70
commit 0728902f90
3 changed files with 33 additions and 59 deletions
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7
gcc/ChangeLog
View File

@ -1,3 +1,10 @@
Wed Jul 18 18:46:30 CEST 2001 Richard Henderson <rth@cygnus.com>
Jan Hubicka <jh@suse.cz>
* flow.c (redirect_edge_and_branch): Bail out on complex edges.
(try_optimize_cfg): Do not remove tail recursive labels before sibcall.
* jump.c (mark_jump_label): Do not forward branches.
Wed Jul 18 18:35:01 CEST 2001 Jan Hubicka <jh@suse.cz>
* cse.c (delete_trivially_dead_insns): Delete the libcall block

45
gcc/flow.c
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@ -1777,6 +1777,9 @@ redirect_edge_and_branch (e, target)
basic_block src = e->src;
rtx insn = src->end;
if (e->flags & EDGE_COMPLEX)
return false;
if (try_redirect_by_replacing_jump (e, target))
return true;
/* Do this fast path late, as we want above code to simplify for cases
@ -3683,30 +3686,15 @@ try_optimize_cfg (mode)
changed = 1;
b = c;
}
/* The fallthru forwarder block can be deleted. */
if (b->pred->pred_next == NULL
&& forwarder_block_p (b)
&& n_basic_blocks > 1
&& (b->pred->flags & EDGE_FALLTHRU)
&& (b->succ->flags & EDGE_FALLTHRU))
{
if (rtl_dump_file)
fprintf (rtl_dump_file, "Deleting fallthru block %i.\n",
b->index);
c = BASIC_BLOCK (i ? i - 1 : i + 1);
redirect_edge_succ (b->pred, b->succ->dest);
flow_delete_block (b);
changed = 1;
b = c;
}
/* Remove code labels no longer used.
Don't do the optimization before sibling calls are discovered,
as some branches may be hidden inside CALL_PLACEHOLDERs. */
if (!(mode & CLEANUP_PRE_SIBCALL)
&& b->pred->pred_next == NULL
if (b->pred->pred_next == NULL
&& (b->pred->flags & EDGE_FALLTHRU)
&& !(b->pred->flags & EDGE_COMPLEX)
&& GET_CODE (b->head) == CODE_LABEL
&& (!(mode & CLEANUP_PRE_SIBCALL)
|| !tail_recursion_label_p (b->head))
/* If previous block does end with condjump jumping to next BB,
we can't delete the label. */
&& (b->pred->src == ENTRY_BLOCK_PTR
@ -3719,12 +3707,31 @@ try_optimize_cfg (mode)
fprintf (rtl_dump_file, "Deleted label in block %i.\n",
b->index);
}
/* The fallthru forwarder block can be deleted. */
if (b->pred->pred_next == NULL
&& forwarder_block_p (b)
&& n_basic_blocks > 1
&& (b->pred->flags & EDGE_FALLTHRU)
&& (b->succ->flags & EDGE_FALLTHRU)
&& GET_CODE (b->head) != CODE_LABEL)
{
if (rtl_dump_file)
fprintf (rtl_dump_file, "Deleting fallthru block %i.\n",
b->index);
c = BASIC_BLOCK (i ? i - 1 : i + 1);
redirect_edge_succ (b->pred, b->succ->dest);
flow_delete_block (b);
changed = 1;
b = c;
}
/* 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
&& !(s->flags & EDGE_COMPLEX)
&& c->pred->pred_next == NULL
/* If the jump insn has side effects,
we can't kill the edge. */

40
gcc/jump.c
View File

@ -1999,8 +1999,6 @@ mark_jump_label (x, insn, in_mem)
case LABEL_REF:
{
rtx label = XEXP (x, 0);
rtx olabel = label;
rtx next;
/* Ignore remaining references to unreachable labels that
have been deleted. */
@ -2015,23 +2013,6 @@ mark_jump_label (x, insn, in_mem)
if (LABEL_REF_NONLOCAL_P (x))
break;
/* If there are other labels following this one,
replace it with the last of the consecutive labels. */
for (next = NEXT_INSN (label); next; next = NEXT_INSN (next))
{
if (GET_CODE (next) == CODE_LABEL)
label = next;
else if (GET_CODE (next) != NOTE)
break;
else if ((NOTE_LINE_NUMBER (next) == NOTE_INSN_LOOP_BEG
|| NOTE_LINE_NUMBER (next) == NOTE_INSN_FUNCTION_END
/* ??? Optional. Disables some optimizations, but
makes gcov output more accurate with -O. */
|| (flag_test_coverage
&& NOTE_LINE_NUMBER (next) > 0)))
break;
}
XEXP (x, 0) = label;
if (! insn || ! INSN_DELETED_P (insn))
++LABEL_NUSES (label);
@ -2042,27 +2023,6 @@ mark_jump_label (x, insn, in_mem)
JUMP_LABEL (insn) = label;
else
{
/* If we've changed the label, update notes accordingly. */
if (label != olabel)
{
rtx note;
/* We may have a REG_LABEL note to indicate that this
instruction uses the label. */
note = find_reg_note (insn, REG_LABEL, olabel);
if (note)
XEXP (note, 0) = label;
/* We may also have a REG_EQUAL note to indicate that
a register is being set to the address of the
label. */
note = find_reg_note (insn, REG_EQUAL, NULL_RTX);
if (note
&& GET_CODE (XEXP (note, 0)) == LABEL_REF
&& XEXP (XEXP (note, 0), 0) == olabel)
XEXP (XEXP (note, 0), 0) = label;
}
/* Add a REG_LABEL note for LABEL unless there already
is one. All uses of a label, except for labels
that are the targets of jumps, must have a