[Bug rtl-optimization/58997] New: ICE on valid code at -O3 on x86_64-linux-gnu (affecting gcc trunk and 4.8.2)

[Bug rtl-optimization/58997] New: ICE on valid code at -O3 on x86_64-linux-gnu (affecting gcc trunk and 4.8.2)

[su at cs dot ucdavis.edu]

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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58997

            Bug ID: 58997
           Summary: ICE on valid code at -O3 on x86_64-linux-gnu
                    (affecting gcc trunk and 4.8.2)
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: rtl-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: su at cs dot ucdavis.edu

The following code causes an ICE when compiled with the current gcc trunk and
4.8.2 at -O3 on x86_64-linux-gnu (in both 32-bit and 64-bit modes). 

It is a regression from 4.8.1. 

$ gcc-trunk -v
Using built-in specs.
COLLECT_GCC=gcc-trunk
COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-unknown-linux-gnu/4.9.0/lto-wrapper
Target: x86_64-unknown-linux-gnu
Configured with: ../gcc-trunk/configure
--enable-languages=c,c++,objc,obj-c++,fortran,lto --disable-werror
--enable-checking=release --with-gmp=/usr/local/gcc-trunk
--with-mpfr=/usr/local/gcc-trunk --with-mpc=/usr/local/gcc-trunk
--with-cloog=/usr/local/gcc-trunk --prefix=/usr/local/gcc-trunk
Thread model: posix
gcc version 4.9.0 20131105 (experimental) [trunk revision 204377] (GCC) 
$ 
$ gcc-trunk -O2 small.c; a.out
$ gcc-4.8.1 -O3 small.c; a.out
$ 
$ gcc-trunk -O3 small.c
small.c: In function ‘foo’:
small.c:18:1: internal compiler error: in simplify_subreg, at
simplify-rtx.c:5901
 }
 ^
0x82fdca simplify_subreg(machine_mode, rtx_def*, machine_mode, unsigned int)
    ../../gcc-trunk/gcc/simplify-rtx.c:5900
0x830169 simplify_gen_subreg(machine_mode, rtx_def*, machine_mode, unsigned
int)
    ../../gcc-trunk/gcc/simplify-rtx.c:6121
0x74a138 iv_subreg
    ../../gcc-trunk/gcc/loop-iv.c:439
0x74a138 iv_analyze_op
    ../../gcc-trunk/gcc/loop-iv.c:1164
0x74a257 iv_analyze_expr(rtx_def*, rtx_def*, machine_mode, rtx_iv*)
    ../../gcc-trunk/gcc/loop-iv.c:971
0x74a8c4 iv_analyze_def
    ../../gcc-trunk/gcc/loop-iv.c:1122
0x749fea iv_analyze_op
    ../../gcc-trunk/gcc/loop-iv.c:1193
0x7516ef may_unswitch_on
    ../../gcc-trunk/gcc/loop-unswitch.c:201
0x7516ef unswitch_single_loop
    ../../gcc-trunk/gcc/loop-unswitch.c:324
0x751c9c unswitch_single_loop
    ../../gcc-trunk/gcc/loop-unswitch.c:379
0x751f30 unswitch_loops()
    ../../gcc-trunk/gcc/loop-unswitch.c:148
0x742cb7 rtl_unswitch
    ../../gcc-trunk/gcc/loop-init.c:537
0x742cb7 execute
    ../../gcc-trunk/gcc/loop-init.c:567
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.
$ 
$ gcc-4.8.2 -O3 small.c; a.out
small.c: In function ‘foo’:
small.c:18:1: internal compiler error: in simplify_subreg, at
simplify-rtx.c:5732
 }
 ^
0x7bf858 simplify_subreg(machine_mode, rtx_def*, machine_mode, unsigned int)
    ../../gcc-4.8.2/gcc/simplify-rtx.c:5731
0x7c5c18 simplify_gen_subreg(machine_mode, rtx_def*, machine_mode, unsigned
int)
    ../../gcc-4.8.2/gcc/simplify-rtx.c:5952
0x6f6438 iv_subreg
    ../../gcc-4.8.2/gcc/loop-iv.c:428
0x6f6438 iv_analyze_op
    ../../gcc-4.8.2/gcc/loop-iv.c:1154
0x6f5a2a iv_analyze_expr(rtx_def*, rtx_def*, machine_mode, rtx_iv*)
    ../../gcc-4.8.2/gcc/loop-iv.c:961
0x6f6094 iv_analyze_def
    ../../gcc-4.8.2/gcc/loop-iv.c:1112
0x6f62ea iv_analyze_op
    ../../gcc-4.8.2/gcc/loop-iv.c:1183
0x6fce35 may_unswitch_on
    ../../gcc-4.8.2/gcc/loop-unswitch.c:201
0x6fce35 unswitch_single_loop
    ../../gcc-4.8.2/gcc/loop-unswitch.c:324
0x6fd3f4 unswitch_single_loop
    ../../gcc-4.8.2/gcc/loop-unswitch.c:379
0x6fd628 unswitch_loops()
    ../../gcc-4.8.2/gcc/loop-unswitch.c:148
0x6f00a7 rtl_unswitch
    ../../gcc-4.8.2/gcc/loop-init.c:453
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.
$ 
$ 


-------------------------------


int a, b, c, e;
short d;
char h;

int
foo ()
{
  for (; b;)
    {
      d = a ? c : 1 % a;
      c = d;
      h = d;
      if (!h) 
    for (; e;)
      ;
    }
  return 0;
}

int
main ()
{
  foo ();
  return 0;
}
>From gcc-bugs-return-433518-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org Tue Nov 05 06:24:23 2013
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From: "PHHargrove at lbl dot gov" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug other/58996] New: [4.9 regression] build failure in libcilkrts
Date: Tue, 05 Nov 2013 06:24:00 -0000
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http://gcc.gnu.org/bugzilla/show_bug.cgi?idX996

            Bug ID: 58996
           Summary: [4.9 regression] build failure in libcilkrts
           Product: gcc
           Version: 4.9.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: other
          Assignee: unassigned at gcc dot gnu.org
          Reporter: PHHargrove at lbl dot gov

I have an ancient x86 system running Red Hat 8.

This system's version of Linux and/or glibc lacks definitions of cpu_set_t and
CPU_SETSIZE:
$ grep -rl -e CPU_SETSIZE -e cpu_set_t /usr/include
[no output]

So, starting very recently, builds from SVN fail as shown below.

Of course I can (and will) work-around with with --disable-libclikrts.
However, I believe a configure probe for the required support would be
appropriate.

-Paul

libtool: compile:  /usr/local/pkg/upc/nightly/compiler/bld/./gcc/xgcc
-B/usr/local/pkg/upc/nightly/compiler/bld/./gcc/
-B/usr/local/pkg/upc/nightly/compiler/install/i686-pc-linux-gnu/bin/
-B/usr/local/pkg/upc/nightly/compiler/install/i686-pc-linux-gnu/lib/ -isystem
/usr/local/pkg/upc/nightly/compiler/install/i686-pc-linux-gnu/include -isystem
/usr/local/pkg/upc/nightly/compiler/install/i686-pc-linux-gnu/sys-include
"-DPACKAGE_NAME=\"Cilk Runtime Library\""
-DPACKAGE_TARNAME=\"cilk-runtime-library\" -DPACKAGE_VERSION=\"2.0\"
"-DPACKAGE_STRING=\"Cilk Runtime Library 2.0\""
-DPACKAGE_BUGREPORT=\"cilk@intel.com\" -DPACKAGE_URL=\"\"
-DPACKAGE=\"cilk-runtime-library\" -DVERSION=\"2.0\" -DSTDC_HEADERS=1
-DHAVE_SYS_TYPES_H=1 -DHAVE_SYS_STAT_H=1 -DHAVE_STDLIB_H=1 -DHAVE_STRING_H=1
-DHAVE_MEMORY_H=1 -DHAVE_STRINGS_H=1 -DHAVE_INTTYPES_H=1 -DHAVE_STDINT_H=1
-DHAVE_UNISTD_H=1 -DHAVE_ALLOCA_H=1 -DHAVE_ALLOCA=1 -DHAVE_DLFCN_H=1
-DLT_OBJDIR=\".libs/\" -I.
-I/usr/local/pkg/upc/nightly/compiler/gupc-src/libcilkrts
-I/usr/local/pkg/upc/nightly/compiler/gupc-src/libcilkrts/include
-I/usr/local/pkg/upc/nightly/compiler/gupc-src/libcilkrts/runtime
-I/usr/local/pkg/upc/nightly/compiler/gupc-src/libcilkrts/runtime/config/x86
-DIN_CILK_RUNTIME=1 -D_Cilk_spawn= -D_Cilk_sync= -D_Cilk_for=for -fcilkplus
-I/usr/local/pkg/upc/nightly/compiler/gupc-src/libcilkrts/include
-I/usr/local/pkg/upc/nightly/compiler/gupc-src/libcilkrts/runtime
-I/usr/local/pkg/upc/nightly/compiler/gupc-src/libcilkrts/runtime/config/x86
-DIN_CILK_RUNTIME=1 -D_Cilk_spawn= -D_Cilk_sync= -D_Cilk_for=for -fcilkplus
-stdÉ9 -O2 -g -O0 -MT os-unix.lo -MD -MP -MF .deps/os-unix.Tpo -c
/usr/local/pkg/upc/nightly/compiler/gupc-src/libcilkrts/runtime/os-unix.c
-fPIC -DPIC -o .libs/os-unix.o
/usr/local/pkg/upc/nightly/compiler/gupc-src/libcilkrts/runtime/os-unix.c: In
function 'linux_get_affinity_count':
/usr/local/pkg/upc/nightly/compiler/gupc-src/libcilkrts/runtime/os-unix.c:311:5:
error: unknown type name 'cpu_set_t'
     cpu_set_t process_mask;
     ^
/usr/local/pkg/upc/nightly/compiler/gupc-src/libcilkrts/runtime/os-unix.c:314:5:
warning: passing argument 3 of 'sched_getaffinity' from incompatible pointer
type [enabled by default]
     int err = sched_getaffinity (tid, sizeof(process_mask),&process_mask);
     ^
In file included from /usr/include/pthread.h:20:0,
                 from
/usr/local/pkg/upc/nightly/compiler/gupc-src/libcilkrts/runtime/os-unix.c:75:
/usr/include/sched.h:72:12: note: expected 'long unsigned int *' but argument
is of type 'int *'
 extern int sched_getaffinity (__pid_t __pid, unsigned int __len,
            ^
/usr/local/pkg/upc/nightly/compiler/gupc-src/libcilkrts/runtime/os-unix.c:328:21:
error: 'CPU_SETSIZE' undeclared (first use in this function)
     for (i = 0; i < CPU_SETSIZE; i++)
                     ^
/usr/local/pkg/upc/nightly/compiler/gupc-src/libcilkrts/runtime/os-unix.c:328:21:
note: each undeclared identifier is reported only once for each function it
appears in
/usr/local/pkg/upc/nightly/compiler/gupc-src/libcilkrts/runtime/os-unix.c:330:9:
warning: implicit declaration of function 'CPU_ISSET'
[-Wimplicit-function-declaration]
         if (CPU_ISSET(i, &process_mask))
         ^
make[2]: *** [os-unix.lo] Error 1

[Bug rtl-optimization/58997] [4.7/4.8/4.9 Regression] ICE on valid code at -O3 on x86_64-linux-gnu (affecting gcc trunk and 4.8.2)

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58997

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rakdver at gcc dot gnu.org
   Target Milestone|---                         |4.7.4
            Summary|ICE on valid code at -O3 on |[4.7/4.8/4.9 Regression]
                   |x86_64-linux-gnu (affecting |ICE on valid code at -O3 on
                   |gcc trunk and 4.8.2)        |x86_64-linux-gnu (affecting
                   |                            |gcc trunk and 4.8.2)

[Bug rtl-optimization/58997] ICE on valid code at -O3 on x86_64-linux-gnu (affecting gcc trunk and 4.8.2)

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58997

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2013-11-05
                 CC|                            |jakub at gcc dot gnu.org
           Assignee|unassigned at gcc dot gnu.org      |jakub at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Created attachment 31158
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=31158&action=edit
gcc49-pr58997.patch

Untested fix.  Likely regressed in r110005.  For IV_UNKNOWN_EXTEND,
get_iv_value
returns value in iv->mode rather than iv->extend_mode, so for iv_subreg we just
need to adjust the last argument to lowpart_subreg.  For iv_extend similarly,
but IMHO (no testcase) if iv->extend is not unknown, but different from
currently required extend, then the code misbehaves too, say for iv->extend
IV_SIGN_EXTEND what get_iv_value returns is say HImode sign extended into
SImode, if we do iv_extend IV_ZERO_EXTEND to say DImode on this, then it would
give us for negative HImode a value with bits 16-31 all set rather than clear.
And, additionally (again, no testcase), the uses in may_unswitch_on I can't see
how we couldn't end up with get_iv_value returning there zero resp. sign
extended op[i], i.e. wider than we want.  If the other IV isn't sign/zero
extended, or is extended to different mode or differently, or if the other
operand is constant (which should be sign extended from the mode), I'd say this
can create invalid RTL or wrong-code.

[Bug rtl-optimization/58997] [4.7/4.8/4.9 Regression] ICE on valid code at -O3 on x86_64-linux-gnu (affecting gcc trunk and 4.8.2)

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58997

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Author: jakub
Date: Tue Nov  5 19:37:51 2013
New Revision: 204413

URL: http://gcc.gnu.org/viewcvs?rev=204413&root=gcc&view=rev
Log:
    PR rtl-optimization/58997
    * loop-iv.c (iv_subreg): For IV_UNKNOWN_EXTEND, expect
    get_iv_value to be in iv->mode rather than iv->extend_mode.
    (iv_extend): Likewise.  Otherwise, if iv->extend != extend,
    use lowpart_subreg on get_iv_value before calling simplify_gen_unary.
    * loop-unswitch.c (may_unswitch_on): Make sure op[i] is in the right
    mode.

    * gcc.c-torture/compile/pr58997.c: New test.

Added:
    trunk/gcc/testsuite/gcc.c-torture/compile/pr58997.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/loop-iv.c
    trunk/gcc/loop-unswitch.c
    trunk/gcc/testsuite/ChangeLog

[Bug rtl-optimization/58997] [4.7 Regression] ICE on valid code at -O3 on x86_64-linux-gnu (affecting gcc trunk and 4.8.2)

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58997

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P2
      Known to work|                            |4.8.3, 4.9.0
            Summary|[4.7/4.8/4.9 Regression]    |[4.7 Regression] ICE on
                   |ICE on valid code at -O3 on |valid code at -O3 on
                   |x86_64-linux-gnu (affecting |x86_64-linux-gnu (affecting
                   |gcc trunk and 4.8.2)        |gcc trunk and 4.8.2)
      Known to fail|                            |4.8.2

[Bug rtl-optimization/58997] [4.7 Regression] ICE on valid code at -O3 on x86_64-linux-gnu (affecting gcc trunk and 4.8.2)

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58997

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED
   Target Milestone|4.7.4                       |4.8.3
      Known to fail|                            |4.7.4

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
Fixed for 4.8.3.