[Bug middle-end/46212] New: Segfault in reg_nonzero_bits_for_combine

[Bug middle-end/46212] New: Segfault in reg_nonzero_bits_for_combine

[rmansfield at qnx dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46212

           Summary: Segfault in reg_nonzero_bits_for_combine
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: rmansfield@qnx.com


$ ./xgcc -v
Using built-in specs.
COLLECT_GCC=./xgcc
Target: i686-pc-linux-gnu
Configured with: ../configure --disable-bootstrap --enable-languages=c
Thread model: posix
gcc version 4.6.0 20101028 (experimental) [trunk revision 166029] (GCC) 

$ ./xgcc -B.   t.c -O3 -Wall  -funroll-all-loops -c -march=i386
xgcc: internal compiler error: Segmentation fault (program cc1)
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

$ gdb --args ./cc1 -quiet -nostdinc  t.c -O3 -Wall -version -funroll-all-loops
GNU gdb (GDB) 7.2-ubuntu
Copyright (C) 2010 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "i686-linux-gnu".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /home/ryan/gnu/gcc/trunk/tmp/gcc/cc1...done.
Breakpoint 1 at 0x81f2b76: file ../../gcc/diagnostic.c, line 881.
Breakpoint 2 at 0x81f2b03: file ../../gcc/diagnostic.c, line 820.
Breakpoint 3 at 0x80b07c8
Breakpoint 4 at 0x80afa98
(gdb) r
Starting program: /home/ryan/gnu/gcc/trunk/tmp/gcc/cc1 -quiet -nostdinc t.c -O3
-Wall -version -funroll-all-loops
GNU C (GCC) version 4.6.0 20101028 (experimental) [trunk revision 166029]
(i686-pc-linux-gnu)
    compiled by GNU C version 4.4.5, GMP version 4.3.2, MPFR version 3.0.0-p3,
MPC version 0.8.2
GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096
GNU C (GCC) version 4.6.0 20101028 (experimental) [trunk revision 166029]
(i686-pc-linux-gnu)
    compiled by GNU C version 4.4.5, GMP version 4.3.2, MPFR version 3.0.0-p3,
MPC version 0.8.2
GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096
Compiler executable checksum: bc9857b210e225a4f4bf75c19a868300

Program received signal SIGSEGV, Segmentation fault.
0x087ed03f in reg_nonzero_bits_for_combine (x=0xb7786090, mode=SImode, 
    known_x=0x0, known_mode=VOIDmode, known_ret=0, nonzero=0xbf60007c)
    at ../../gcc/combine.c:9406
9406      tem = get_last_value (x);
(gdb) bt
#0  0x087ed03f in reg_nonzero_bits_for_combine (x=0xb7786090, mode=SImode, 
    known_x=0x0, known_mode=VOIDmode, known_ret=0, nonzero=0xbf60007c)
    at ../../gcc/combine.c:9406
#1  0x083ecb28 in nonzero_bits1 (x=0xb7786090, mode=SImode, 
    known_x=<value optimized out>, known_mode=VOIDmode, known_ret=0)
    at ../../gcc/rtlanal.c:3791
#2  0x083ecfc6 in num_sign_bit_copies1 (x=0xb7786090, 
    mode=<value optimized out>, known_x=<value optimized out>, 
    known_mode=VOIDmode, known_ret=0) at ../../gcc/rtlanal.c:4627
#3  0x087eefbf in if_then_else_cond (x=0xb7786090, 
    ptrue=<value optimized out>, pfalse=<value optimized out>)
    at ../../gcc/combine.c:8653
#4  0x087eee7e in if_then_else_cond (x=0xb76bad50, 
    ptrue=<value optimized out>, pfalse=<value optimized out>)
    at ../../gcc/combine.c:8507
#5  0x087eee7e in if_then_else_cond (x=0xb76bad74, 
    ptrue=<value optimized out>, pfalse=<value optimized out>)
    at ../../gcc/combine.c:8507
#6  0x087ef08e in if_then_else_cond (x=0xb7698a98, 
    ptrue=<value optimized out>, pfalse=<value optimized out>)
    at ../../gcc/combine.c:8620
#7  0x087ef01e in if_then_else_cond (x=0xb76a1368, 
    ptrue=<value optimized out>, pfalse=<value optimized out>)

[Bug middle-end/46212] Segfault in reg_nonzero_bits_for_combine

[rmansfield at qnx dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46212

--- Comment #1 from Ryan Mansfield <rmansfield at qnx dot com> 2010-10-28 17:37:25 UTC ---
Working on reducing the testcase. I originally encountered the ICE as:

internal compiler error: vector VEC(reg_stat_type,base) index domain error, in
reg_nonzero_bits_for_combine at combine.c:9385

but as I reduce the test case becomes a segfault.

[Bug middle-end/46212] Segfault in reg_nonzero_bits_for_combine

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46212

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         Depends on|                            |46034

--- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> 2010-10-28 17:40:18 UTC ---
This is most likely a duplicate of bug 46034.

[Bug middle-end/46212] Segfault in reg_nonzero_bits_for_combine

[rmansfield at qnx dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46212

--- Comment #3 from Ryan Mansfield <rmansfield at qnx dot com> 2010-10-28 18:45:10 UTC ---
Reduced testcase:

static __inline__ unsigned foo(void *__ptr) {
   unsigned __val = *(volatile unsigned *)(__ptr);
   return (((__val) >> 24) | (((__val) >> 8) & 0xff00) |  (((__val) & 0xff00)
<< 8) | ((__val) << 24));
}

void bar(void *dst, void *src, int pixels) {
  unsigned c;
  while (pixels--) {
   c = foo(src);
   *(unsigned *)dst = (c & 0xf80000) >> 9 | (c & 0xf800) >> 6 | (c & 0xf8) >> 3
| (c & 0x80000000) >> 16;
  }
}

Looks like the same bug. Sorry for the dup. I only searched bugzilla for PRs
about reg_nonzero_bits_for_combine.

[Bug rtl-optimization/46212] Segfault in reg_nonzero_bits_for_combine

[ebotcazou at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46212

Eric Botcazou <ebotcazou at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2010.10.29 12:45:59
                 CC|                            |ebotcazou at gcc dot
                   |                            |gnu.org
          Component|middle-end                  |rtl-optimization
         AssignedTo|unassigned at gcc dot       |ebotcazou at gcc dot
                   |gnu.org                     |gnu.org
     Ever Confirmed|0                           |1

--- Comment #4 from Eric Botcazou <ebotcazou at gcc dot gnu.org> 2010-10-29 12:45:59 UTC ---
Investigating.

[Bug rtl-optimization/46212] [4.6 regression] segfault in reg_nonzero_bits_for_combine

[hjl.tools at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46212

H.J. Lu <hjl.tools at gmail dot com> changed:

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

--- Comment #5 from H.J. Lu <hjl.tools at gmail dot com> 2010-10-31 15:49:57 UTC ---
It is caused by revision 165674:

http://gcc.gnu.org/ml/gcc-cvs/2010-10/msg00859.html

[Bug rtl-optimization/46212] [4.6 regression] segfault in reg_nonzero_bits_for_combine

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46212

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> 2010-11-01 11:24:12 UTC ---
Created attachment 22217
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22217
gcc46-pr46034.patch

Untested fix.

[Bug rtl-optimization/46212] [4.6 regression] segfault in reg_nonzero_bits_for_combine

[ebotcazou at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46212

Eric Botcazou <ebotcazou at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |NEW
         AssignedTo|ebotcazou at gcc dot        |unassigned at gcc dot
                   |gnu.org                     |gnu.org

[Bug rtl-optimization/46212] [4.6 regression] segfault in reg_nonzero_bits_for_combine

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46212

--- Comment #7 from Jakub Jelinek <jakub at gcc dot gnu.org> 2010-11-03 08:30:29 UTC ---
Author: jakub
Date: Wed Nov  3 08:30:21 2010
New Revision: 166231

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=166231
Log:
    PR rtl-optimization/46034
    PR rtl-optimization/46212
    PR rtl-optimization/46248
    * combine.c (try_combine): If added_sets_2 where i0dest_in_i0src
    and i0 feeds i1 and i1 feeds i2 or i0 feeds i2, make a copy of i1src
    before i0dest -> i0src substitution and pass 1 instead of 0 as last
    argument to subst on i2pat.

    * gcc.c-torture/compile/pr46034.c: New test.
    * gcc.c-torture/compile/pr46248.c: New test.
    * gcc.dg/pr46212.c: New test.

Added:
    trunk/gcc/testsuite/gcc.c-torture/compile/pr46034.c
    trunk/gcc/testsuite/gcc.c-torture/compile/pr46248.c
    trunk/gcc/testsuite/gcc.dg/pr46212.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/combine.c
    trunk/gcc/testsuite/ChangeLog

[Bug rtl-optimization/46212] [4.6 regression] segfault in reg_nonzero_bits_for_combine

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46212

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |jakub at gcc dot gnu.org
         Resolution|                            |FIXED

--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> 2010-11-03 08:45:28 UTC ---
Fixed.