This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: avoid try_split recursion on sequence
- To: grahams <grahams at rcp dot co dot uk>
- Subject: Re: avoid try_split recursion on sequence
- From: Clinton Popetz <cpopetz at cygnus dot com>
- Date: Thu, 13 Apr 2000 14:57:37 -0500
- Cc: gcc-patches at gcc dot gnu dot org
- References: <20000413140812.A10762@cpopetz.com> <38F61D58.D1A51861@rcp.co.uk>
On Thu, Apr 13, 2000 at 08:17:44PM +0100, grahams wrote:
> Clint
>
> Clinton Popetz wrote:
> >
> > I found a case where an attempted split would result in a sequence, the first
> > insn of which was equal to the original insn, so emit-rtl would recurse
> > infinitely. This behavior is explicitly avoided in the simple (non-sequence
> > case), so its seems appropriate to do the same in the sequence case.
> >
> > Ok?
> >
> > -Clint
> >
>
> Would it not be prudent to check all insns in the sequence and not just the
> first insn.
>
> Graham
Yup. The prior patch fixed my bug, and tunnel vision kicked in :)
-Clint
Thu Apr 13 14:03:03 CDT 2000 Clinton Popetz <cpopetz@cygnus.com>
* emit-rtl.c (try_split): Avoid infinite loop if the split
results in a sequence that contains the original insn.
Index: emit-rtl.c
===================================================================
RCS file: /cvs/gcc/egcs/gcc/emit-rtl.c,v
retrieving revision 1.124
diff -c -2 -p -r1.124 emit-rtl.c
*** emit-rtl.c 2000/04/10 11:51:53 1.124
--- emit-rtl.c 2000/04/13 19:39:44
*************** try_split (pat, trial, last)
*** 2337,2344 ****
if (GET_CODE (seq) == SEQUENCE)
{
/* If we are splitting a JUMP_INSN, look for the JUMP_INSN in
SEQ and copy our JUMP_LABEL to it. If JUMP_LABEL is non-zero,
increment the usage count so we don't delete the label. */
- int i;
if (GET_CODE (trial) == JUMP_INSN)
--- 2337,2352 ----
if (GET_CODE (seq) == SEQUENCE)
{
+ int i;
+
+ /* Avoid infinite loop if any insn of the result matches
+ the original pattern. */
+ for (i = 0; i < XVECLEN (seq, 0); i++)
+ if (GET_CODE (XVECEXP (seq, 0, i)) == INSN
+ && rtx_equal_p (PATTERN (XVECEXP (seq, 0, i)), pat))
+ return trial;
+
/* If we are splitting a JUMP_INSN, look for the JUMP_INSN in
SEQ and copy our JUMP_LABEL to it. If JUMP_LABEL is non-zero,
increment the usage count so we don't delete the label. */
if (GET_CODE (trial) == JUMP_INSN)