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flow.c (last_loop_beg_note): New function. 

* flow.c (last_loop_beg_note): New function.
	(redirect_edge_and_branch): Use it.
	(split_edge): Likewise.

	* alias.c (loop_p): Avoid uninitialized memory access.

	* flow.c (try_forward_edges): Avoid accessing freed memory.

	* flow.c (backward_edge_of_syntactic_loop_p): Avoid uninitialized
	variable access.

From-SVN: r44429
This commit is contained in:
Jan Hubicka 2001-07-27 17:55:41 +02:00 committed by Jan Hubicka
parent f636e2a57d
commit d69d031618
3 changed files with 73 additions and 26 deletions
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13
gcc/ChangeLog
View File

@ -1,3 +1,16 @@
Fri Jul 27 17:53:00 CEST 2001 Jan Hubicka <jh@suse.cz>
* flow.c (last_loop_beg_note): New function.
(redirect_edge_and_branch): Use it.
(split_edge): Likewise.
* alias.c (loop_p): Avoid uninitialized memory access.
* flow.c (try_forward_edges): Avoid accessing freed memory.
* flow.c (backward_edge_of_syntactic_loop_p): Avoid uninitialized
variable access.
2001-07-27 Gerald Pfeifer <pfeifer@dbai.tuwien.ac.at>
* doc/install.texi (Configuration): Properly link the host

2
gcc/alias.c
View File

@ -2118,7 +2118,7 @@ loop_p ()
}
else
{
if (dest != EXIT_BLOCK_PTR
if (dest != EXIT_BLOCK_PTR && src != ENTRY_BLOCK_PTR
&& pre[src->index] >= pre[dest->index]
&& post[dest->index] == 0)
break;

84
gcc/flow.c
View File

@ -1748,6 +1748,30 @@ try_redirect_by_replacing_jump (e, target)
return true;
}
/* Return last loop_beg note appearing after INSN, before start of next
basic block. Return INSN if there are no such notes.
When emmiting jump to redirect an fallthru edge, it should always
appear after the LOOP_BEG notes, as loop optimizer expect loop to
eighter start by fallthru edge or jump following the LOOP_BEG note
jumping to the loop exit test.
*/
rtx
last_loop_beg_note (insn)
rtx insn;
{
rtx last = insn;
insn = NEXT_INSN (insn);
while (GET_CODE (insn) == NOTE
&& NOTE_LINE_NUMBER (insn) != NOTE_INSN_BASIC_BLOCK)
{
if (NOTE_LINE_NUMBER (insn) == NOTE_INSN_LOOP_BEG)
last = insn;
insn = NEXT_INSN (insn);
}
return last;
}
/* Attempt to change code to redirect edge E to TARGET.
Don't do that on expense of adding new instructions or reordering
basic blocks.
@ -1877,7 +1901,8 @@ redirect_edge_and_branch_force (e, target)
/* Case of the fallthru block. */
if (!e->src->succ->succ_next)
{
e->src->end = emit_jump_insn_after (gen_jump (label), e->src->end);
e->src->end = emit_jump_insn_after (gen_jump (label),
last_loop_beg_note (e->src->end));
JUMP_LABEL (e->src->end) = label;
LABEL_NUSES (label)++;
if (basic_block_for_insn)
@ -1906,7 +1931,7 @@ redirect_edge_and_branch_force (e, target)
memset (new_bb, 0, sizeof (*new_bb));
new_bb->end = new_bb->head = e->src->end;
new_bb->end = new_bb->head = last_loop_beg_note (e->src->end);
new_bb->succ = NULL;
new_bb->pred = new_edge;
new_bb->count = e->count;
@ -1976,7 +2001,7 @@ back_edge_of_syntactic_loop_p (bb1, bb2)
basic_block bb1, bb2;
{
rtx insn;
int count;
int count = 0;
if (bb1->index > bb2->index)
return false;
if (bb1->index == bb2->index)
@ -2088,7 +2113,7 @@ split_edge (edge_in)
/* Now add the jump insn ... */
pos = emit_jump_insn_after (gen_jump (old_succ->head),
jump_block->end);
last_loop_beg_note (jump_block->end));
jump_block->end = pos;
if (basic_block_for_insn)
set_block_for_new_insns (pos, jump_block);
@ -3159,29 +3184,38 @@ try_forward_edges (b)
}
else if (target == first)
; /* We didn't do anything. */
else if (redirect_edge_and_branch (e, target))
{
/* We successfully forwarded the edge. Now update profile
data: for each edge we traversed in the chain, remove
the original edge's execution count. */
do
{
first->count -= e->count;
first->succ->count -= e->count;
first->frequency -= ((e->probability * b->frequency
+ REG_BR_PROB_BASE / 2)
/ REG_BR_PROB_BASE);
first = first->succ->dest;
}
while (first != target);
changed = true;
}
else
{
if (rtl_dump_file)
fprintf (rtl_dump_file, "Forwarding edge %i->%i to %i failed.\n",
b->index, e->dest->index, target->index);
/* Save the values now, as the edge may get removed. */
gcov_type edge_count = e->count;
int edge_probability = e->probability;
if (redirect_edge_and_branch (e, target))
{
/* We successfully forwarded the edge. Now update profile
data: for each edge we traversed in the chain, remove
the original edge's execution count. */
int edge_frequency = ((edge_probability * b->frequency
+ REG_BR_PROB_BASE / 2)
/ REG_BR_PROB_BASE);
do
{
first->count -= edge_count;
first->succ->count -= edge_count;
first->frequency -= edge_frequency;
first = first->succ->dest;
}
while (first != target);
changed = true;
}
else
{
if (rtl_dump_file)
fprintf (rtl_dump_file, "Forwarding edge %i->%i to %i failed.\n",
b->index, e->dest->index, target->index);
}
}
}