[Bug rtl-optimization/48374] New: ICE: in single_succ_edge, at basic-block.h:562 with -fselective-scheduling2 and __builtin_unreachable()

[Bug rtl-optimization/48374] New: ICE: in single_succ_edge, at basic-block.h:562 with -fselective-scheduling2 and __builtin_unreachable()

[zsojka at seznam dot cz]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48374

           Summary: ICE: in single_succ_edge, at basic-block.h:562 with
                    -fselective-scheduling2 and __builtin_unreachable()
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: zsojka@seznam.cz
              Host: x86_64-pc-linux-gnu
            Target: x86_64-pc-linux-gnu


Created attachment 23824
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=23824
reduced testcase

Compiler output:
$ gcc -O -fschedule-insns2 -fsel-sched-pipelining
-fsel-sched-pipelining-outer-loops -fselective-scheduling2 --param
max-sched-extend-regions-iters=100 testcase.c 
testcase.c: In function 'foo':
testcase.c:14:1: internal compiler error: in single_succ_edge, at
basic-block.h:562
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

Tested revisions:
r171735 - crash
4.6 r171597 - crash
4.5 r171597 - crash
4.4 r171597 - doesn't know __builtin_unreachable

[Bug rtl-optimization/48374] ICE: in single_succ_edge, at basic-block.h:562 with -fselective-scheduling2 and __builtin_unreachable()

[abel at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48374

Andrey Belevantsev <abel at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2011.04.07 07:45:54
                 CC|                            |abel at gcc dot gnu.org
         AssignedTo|unassigned at gcc dot       |abel at gcc dot gnu.org
                   |gnu.org                     |
     Ever Confirmed|0                           |1

--- Comment #1 from Andrey Belevantsev <abel at gcc dot gnu.org> 2011-04-07 07:45:54 UTC ---
Confirmed, yet another case when we don't expect a block with zero successors. 
The following fixes the problem.

Btw, --param max-sched-extend-regions-iters=2 is enough to reproduce the bug. 
Zdenek, for most functions you don't want more than two iterations (you can see
the comment in sched-rgn.c:1248, so in your experiments you can limit it to not
more than 5-10.  You actually need a positive value for the region extension
code to fire though.

diff --git a/gcc/sel-sched-ir.h b/gcc/sel-sched-ir.h
index 5516da9..13af1b5 100644
--- a/gcc/sel-sched-ir.h
+++ b/gcc/sel-sched-ir.h
@@ -1119,7 +1119,8 @@ get_all_loop_exits (basic_block bb)
   /* If bb is empty, and we're skipping to loop exits, then
      consider bb as a possible gate to the inner loop now.  */
   while (sel_bb_empty_or_nop_p (bb)
-        && in_current_region_p (bb))
+        && in_current_region_p (bb)
+        && EDGE_COUNT (bb->succs) > 0)
     {
       bb = single_succ (bb);

[Bug rtl-optimization/48374] ICE: in single_succ_edge, at basic-block.h:562 with -fselective-scheduling2 and __builtin_unreachable()

[zsojka at seznam dot cz]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48374

--- Comment #2 from Zdenek Sojka <zsojka at seznam dot cz> 2011-05-10 18:05:57 UTC ---
Thanks for the suggestion, Andrey. Using lower values for --param
max-sched-extend-regions-iters might reduce the compilation time in some cases.

I tested your patch on top of r173588 and it fixes the ICE on all testcases I
have.

[Bug rtl-optimization/48374] ICE: in single_succ_edge, at basic-block.h:562 with -fselective-scheduling2 and __builtin_unreachable()

[abel at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48374

--- Comment #3 from Andrey Belevantsev <abel at gcc dot gnu.org> 2012-01-25 13:20:47 UTC ---
Author: abel
Date: Wed Jan 25 13:20:43 2012
New Revision: 183519

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=183519
Log:
gcc:
    PR rtl-optimization/48374
        * sel-sched-ir.h (get_all_loop_exits): Check for zero successors.

testsuite:
        PR rtl-optimization/48374
        * gcc.dg/pr48374.c: New test.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/sel-sched-ir.h
    trunk/gcc/testsuite/ChangeLog

[Bug rtl-optimization/48374] ICE: in single_succ_edge, at basic-block.h:562 with -fselective-scheduling2 and __builtin_unreachable()

[mikpe at it dot uu.se]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48374

--- Comment #4 from Mikael Pettersson <mikpe at it dot uu.se> 2012-02-05 17:51:49 UTC ---
Seems you forgot to actually add the test case.

[Bug rtl-optimization/48374] ICE: in single_succ_edge, at basic-block.h:562 with -fselective-scheduling2 and __builtin_unreachable()

[abel at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48374

--- Comment #5 from Andrey Belevantsev <abel at gcc dot gnu.org> 2012-02-06 08:32:30 UTC ---
(In reply to comment #4)
> Seems you forgot to actually add the test case.

Thanks, I forgot to svn add, fixed in 183928.

[Bug rtl-optimization/48374] ICE: in single_succ_edge, at basic-block.h:562 with -fselective-scheduling2 and __builtin_unreachable()

[abel at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48374

Andrey Belevantsev <abel at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED

--- Comment #7 from Andrey Belevantsev <abel at gcc dot gnu.org> 2012-10-30 08:26:36 UTC ---
Finally fixed in 4.6 too, closed.

[Bug rtl-optimization/48374] ICE: in single_succ_edge, at basic-block.h:562 with -fselective-scheduling2 and __builtin_unreachable()

[abel at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=48374

--- Comment #6 from Andrey Belevantsev <abel at gcc dot gnu.org> 2012-10-30 08:25:24 UTC ---
Author: abel
Date: Tue Oct 30 08:25:16 2012
New Revision: 192979

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=192979
Log:
        Backport from mainline
        2012-01-25 Andrey Belevantsev <abel@ispras.ru>

        PR rtl-optimization/48374
        * sel-sched-ir.h (get_all_loop_exits): Check for zero successors.

        * gcc.dg/pr48374.c: New test.



Added:
    branches/gcc-4_6-branch/gcc/testsuite/gcc.dg/pr48374.c
Modified:
    branches/gcc-4_6-branch/gcc/ChangeLog
    branches/gcc-4_6-branch/gcc/sel-sched-ir.h
    branches/gcc-4_6-branch/gcc/testsuite/ChangeLog