[Bug middle-end/46637] New: [4.6 Regression] SIGSEGV in if_then_else_cond - too deep recursion

[Bug middle-end/46637] New: [4.6 Regression] SIGSEGV in if_then_else_cond - too deep recursion

[d.g.gorbachev at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46637

           Summary: [4.6 Regression] SIGSEGV in if_then_else_cond - too
                    deep recursion
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: d.g.gorbachev@gmail.com
              Host: i686-pc-linux-gnu-gcc
            Target: i686-pc-linux-gnu-gcc
             Build: i686-pc-linux-gnu-gcc


Created attachment 22505
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22505
Preprocessed Linux source file (in bzip2 format)

Compile with:

gcc -m32 -msoft-float -mregparm=3 -mpreferred-stack-boundary=2
-fno-strict-aliasing -fno-common -fno-delete-null-pointer-checks
-freg-struct-return -ffreestanding -fno-asynchronous-unwind-tables
-fno-stack-protector -fno-omit-frame-pointer -fno-optimize-sibling-calls
-fno-strict-overflow -fconserve-stack -Os tcp_input.i

[Bug middle-end/46637] [4.6 Regression] SIGSEGV in if_then_else_cond - too deep recursion

[d.g.gorbachev at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46637

--- Comment #1 from Dmitry Gorbachev <d.g.gorbachev at gmail dot com> 2010-11-24 06:59:44 UTC ---
Created attachment 22506
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22506
Backtrace in GDB

[Bug middle-end/46637] [4.6 Regression] SIGSEGV in if_then_else_cond - too deep recursion

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46637

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> 2010-11-24 10:32:26 UTC ---
Reducing...

[Bug middle-end/46637] [4.6 Regression] SIGSEGV in if_then_else_cond - too deep recursion

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46637

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.6.0

[Bug middle-end/46637] [4.6 Regression] SIGSEGV in if_then_else_cond - too deep recursion

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46637

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> 2010-11-24 12:38:20 UTC ---
Reduced testcase, fails on x86_64-linux with -m32 and -O{2,s}
{,-fno-strict-aliasing}.  Looking into it...

struct S { unsigned s[5]; } *p;

void
foo (int x)
{
  int a = x == 1 ? 4 : 1;
  asm ("" : "+m" (p->s[a]));
  *(unsigned *) p += 1;
}

[Bug middle-end/46637] [4.6 Regression] SIGSEGV in if_then_else_cond - too deep recursion

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46637

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2010.11.24 13:45:43
         AssignedTo|unassigned at gcc dot       |jakub at gcc dot gnu.org
                   |gnu.org                     |
     Ever Confirmed|0                           |1

--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> 2010-11-24 13:45:43 UTC ---
Created attachment 22510
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22510
gcc46-pr46637.patch

Untested fix.

[Bug middle-end/46637] [4.6 Regression] SIGSEGV in if_then_else_cond - too deep recursion

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46637

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> 2010-11-25 18:01:00 UTC ---
Author: jakub
Date: Thu Nov 25 18:00:47 2010
New Revision: 167148

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=167148
Log:
    PR middle-end/46637
    * combine.c (try_combine): When substing i2dest for i2src, pass
    1 as last argument even if
    i0_feeds_i1_n && i1_feeds_i2_n && i0dest_in_i0src.

    * gcc.c-torture/compile/pr46637.c: New test.

Added:
    trunk/gcc/testsuite/gcc.c-torture/compile/pr46637.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/combine.c
    trunk/gcc/testsuite/ChangeLog

[Bug middle-end/46637] [4.6 Regression] SIGSEGV in if_then_else_cond - too deep recursion

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46637

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

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

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> 2010-11-25 18:12:59 UTC ---
Fixed.