[Bug rtl-optimization/50205] New: [4.6/4.7 Regression] ICE: in code_motion_path_driver, at sel-sched.c:6581 with -fselective-scheduling2 and custom flags

[Bug rtl-optimization/50205] New: [4.6/4.7 Regression] ICE: in code_motion_path_driver, at sel-sched.c:6581 with -fselective-scheduling2 and custom flags

[zsojka at seznam dot cz]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50205

             Bug #: 50205
           Summary: [4.6/4.7 Regression] ICE: in code_motion_path_driver,
                    at sel-sched.c:6581 with -fselective-scheduling2 and
                    custom flags
    Classification: Unclassified
           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 25115
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=25115
reduced testcase

Compiler output:
$ gcc -O2 -fno-cprop-registers -fno-dce -fno-forward-propagate
-fselective-scheduling2 -funroll-loops -fno-web testcase.c         
testcase.c: In function 'foo':
testcase.c:11:1: internal compiler error: in code_motion_path_driver, at
sel-sched.c:6581
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

Tested revisions:
r178096 - crash
4.6 r177922 - crash
4.5 r177922 - OK

[Bug rtl-optimization/50205] [4.6/4.7 Regression] ICE: in code_motion_path_driver, at sel-sched.c:6581 with -fselective-scheduling2 and custom flags

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50205

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.6.2

[Bug rtl-optimization/50205] [4.6/4.7 Regression] ICE: in code_motion_path_driver, at sel-sched.c:6581 with -fselective-scheduling2 and custom flags

[amonakov at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50205

Alexander Monakov <amonakov at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2011-09-06
                 CC|                            |abel at gcc dot gnu.org,
                   |                            |amonakov at gcc dot gnu.org
         AssignedTo|unassigned at gcc dot       |amonakov at gcc dot gnu.org
                   |gnu.org                     |
     Ever Confirmed|0                           |1

--- Comment #1 from Alexander Monakov <amonakov at gcc dot gnu.org> 2011-09-06 11:17:47 UTC ---
We attempt to substitute an insn like (... (cmp (mem (reg:DI ax)) (reg:SI ax)))
(note different modes) through (set (reg:DI ax) (reg:DI dx)), which leaves the
(reg:SI ax) part of the comparison intact, causing an ICE later on when we
notice that the dependency on ax is still present.  As this is quite rare, we
can simply forbid substitution in such circumstances, much like substitution of
multiple hard reg references is forbidden now.  The patch I'm going to test:

diff --git a/gcc/sel-sched.c b/gcc/sel-sched.c
index f11faca..2af01ae 100644
--- a/gcc/sel-sched.c
+++ b/gcc/sel-sched.c
@@ -813,18 +813,12 @@ count_occurrences_1 (rtx *cur_rtx, void *arg)
 {
   rtx_search_arg_p p = (rtx_search_arg_p) arg;

-  /* The last param FOR_GCSE is true, because otherwise it performs excessive
-    substitutions like
-    r8 = r33
-    r16 = r33
-    for the last insn it presumes r33 equivalent to r8, so it changes it to
-    r33.  Actually, there's no change, but it spoils debugging.  */
-  if (exp_equiv_p (*cur_rtx, p->x, 0, true))
-    {
-      /* Bail out if we occupy more than one register.  */
-      if (REG_P (*cur_rtx)
-          && HARD_REGISTER_P (*cur_rtx)
-          && hard_regno_nregs[REGNO(*cur_rtx)][GET_MODE (*cur_rtx)] > 1)
+  if (REG_P (*cur_rtx) && REGNO (*cur_rtx) == REGNO (p->x))
+    {
+      /* Bail out if mode is different or more than one register is used.  */
+      if (GET_MODE (*cur_rtx) != GET_MODE (p->x)
+          || (HARD_REGISTER_P (*cur_rtx)
+          && hard_regno_nregs[REGNO(*cur_rtx)][GET_MODE (*cur_rtx)] > 1))
         {
           p->n = 0;
           return 1;
@@ -837,7 +831,6 @@ count_occurrences_1 (rtx *cur_rtx, void *arg)
     }

   if (GET_CODE (*cur_rtx) == SUBREG
-      && REG_P (p->x)
       && (!REG_P (SUBREG_REG (*cur_rtx))
       || REGNO (SUBREG_REG (*cur_rtx)) == REGNO (p->x)))
     {
@@ -859,6 +852,7 @@ count_occurrences_equiv (rtx what, rtx where)
 {
   struct rtx_search_arg arg;

+  gcc_assert (REG_P (what));
   arg.x = what;
   arg.n = 0;

[Bug rtl-optimization/50205] [4.6/4.7 Regression] ICE: in code_motion_path_driver, at sel-sched.c:6581 with -fselective-scheduling2 and custom flags

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50205

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2

[Bug rtl-optimization/50205] [4.6/4.7 Regression] ICE: in code_motion_path_driver, at sel-sched.c:6581 with -fselective-scheduling2 and custom flags

[amonakov at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50205

--- Comment #2 from Alexander Monakov <amonakov at gcc dot gnu.org> 2011-10-18 12:36:20 UTC ---
Author: amonakov
Date: Tue Oct 18 12:36:16 2011
New Revision: 180135

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=180135
Log:
    PR rtl-optimization/50205
    * sel-sched.c (count_occurrences_1): Simplify on the assumption that
    p->x is a register.  Forbid substitution when the same register is
    found in a different mode.
    (count_occurrences_equiv): Assert that 'what' is a register.

    * gcc.dg/pr50205.c: New.

Added:
    trunk/gcc/testsuite/gcc.dg/pr50205.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/sel-sched.c
    trunk/gcc/testsuite/ChangeLog

[Bug rtl-optimization/50205] [4.6/4.7 Regression] ICE: in code_motion_path_driver, at sel-sched.c:6581 with -fselective-scheduling2 and custom flags

[amonakov at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50205

Alexander Monakov <amonakov at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P2                          |P3
      Known to work|                            |4.7.0
      Known to fail|4.7.0                       |

--- Comment #3 from Alexander Monakov <amonakov at gcc dot gnu.org> 2011-10-18 12:45:14 UTC ---
Fixed on the trunk, needs backport to 4.6

[Bug rtl-optimization/50205] [4.6/4.7 Regression] ICE: in code_motion_path_driver, at sel-sched.c:6581 with -fselective-scheduling2 and custom flags

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50205

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.6.2                       |4.6.3

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-10-26 17:13:54 UTC ---
GCC 4.6.2 is being released.

[Bug rtl-optimization/50205] [4.6 Regression] ICE: in code_motion_path_driver, at sel-sched.c:6581 with -fselective-scheduling2 and custom flags

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50205

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2
            Summary|[4.6/4.7 Regression] ICE:   |[4.6 Regression] ICE: in
                   |in code_motion_path_driver, |code_motion_path_driver, at
                   |at sel-sched.c:6581 with    |sel-sched.c:6581 with
                   |-fselective-scheduling2 and |-fselective-scheduling2 and
                   |custom flags                |custom flags

[Bug rtl-optimization/50205] [4.6 Regression] ICE: in code_motion_path_driver, at sel-sched.c:6581 with -fselective-scheduling2 and custom flags

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50205

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|4.6.3                       |4.6.4

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-03-01 14:39:13 UTC ---
GCC 4.6.3 is being released.

[Bug rtl-optimization/50205] [4.6 Regression] ICE: in code_motion_path_driver, at sel-sched.c:6581 with -fselective-scheduling2 and custom flags

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50205

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|4.6.4                       |4.7.0

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> 2013-04-12 16:17:58 UTC ---
The 4.6 branch has been closed, fixed in GCC 4.7.0.