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(find_and_verify_loops): When moving blocks of code, verify that the just destination is not in an inner nested loop. 

(find_and_verify_loops): When moving blocks of code, verify that the
just destination is not in an inner nested loop.
(mark_loop_jump): Don't mark label as loop exit if it jumps to an
inner nested loop.

From-SVN: r10164
This commit is contained in:
Richard Kenner 1995-07-26 08:43:24 -04:00
parent aa6b6385f2
commit edf711a4e4
1 changed files with 30 additions and 2 deletions
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32
gcc/loop.c
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@ -2338,6 +2338,8 @@ find_and_verify_loops (f)
{
rtx p;
rtx our_next = next_real_insn (insn);
int dest_loop = uid_loop_num[INSN_UID (JUMP_LABEL (insn))];
int outer_loop;
/* Go backwards until we reach the start of the loop, a label,
or a JUMP_INSN. */
@ -2349,6 +2351,19 @@ find_and_verify_loops (f)
p = PREV_INSN (p))
;
/* Check for the case where we have a jump to an inner nested
loop, and do not perform the optimization in that case. */
if (dest_loop != -1)
{
for (outer_loop = dest_loop; outer_loop != -1;
outer_loop = loop_outer_loop[outer_loop])
if (outer_loop == this_loop_num)
break;
}
else
outer_loop = -1;
/* If we stopped on a JUMP_INSN to the next insn after INSN,
we have a block of code to try to move.
@ -2358,7 +2373,8 @@ find_and_verify_loops (f)
of the block, invert the jump in P and point it to that label,
and move the block of code to the spot we found. */
if (GET_CODE (p) == JUMP_INSN
if (outer_loop == -1
&& GET_CODE (p) == JUMP_INSN
&& JUMP_LABEL (p) != 0
/* Just ignore jumps to labels that were never emitted.
These always indicate compilation errors. */
@ -2522,7 +2538,19 @@ mark_loop_jump (x, loop_num)
mark this LABEL_REF so we know that this branch should predict
false. */
if (dest_loop != loop_num && loop_num != -1)
/* A check to make sure the label is not in an inner nested loop,
since this does not count as a loop exit. */
if (dest_loop != -1)
{
for (outer_loop = dest_loop; outer_loop != -1;
outer_loop = loop_outer_loop[outer_loop])
if (outer_loop == loop_num)
break;
}
else
outer_loop = -1;
if (loop_num != -1 && outer_loop == -1)
{
LABEL_OUTSIDE_LOOP_P (x) = 1;
LABEL_NEXTREF (x) = loop_number_exit_labels[loop_num];