[Bug target/56184] New: Internal compiler error in push_reload during bootstrap stage 2

[Bug target/56184] New: Internal compiler error in push_reload during bootstrap stage 2

[mgretton at sourceware dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56184

             Bug #: 56184
           Summary: Internal compiler error in push_reload during
                    bootstrap stage 2
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: target
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: mgretton@sourceware.org


Created attachment 29337
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=29337
Reduced test case

When bootstrapping on an ARM target I get the following error:

/cbuild/slaves/tcpandas/gcc-4.8~svn195568/gcc/default/build/./prev-gcc/xg++
-B/cbuild/slaves/tcpandas/gcc-4.8~svn195568/gcc/default/build/./prev-gcc/
-B/cbuild/slaves/tcpandas/gcc-4.8~svn195568/gcc/default/install/arm-linux-gnueabi/bin/
-nostdinc++
-B/cbuild/slaves/tcpandas/gcc-4.8~svn195568/gcc/default/build/prev-arm-linux-gnueabi/libstdc++-v3/src/.libs
-B/cbuild/slaves/tcpandas/gcc-4.8~svn195568/gcc/default/build/prev-arm-linux-gnueabi/libstdc++-v3/libsupc++/.libs
-I/cbuild/slaves/tcpandas/gcc-4.8~svn195568/gcc/default/build/prev-arm-linux-gnueabi/libstdc++-v3/include/arm-linux-gnueabi
-I/cbuild/slaves/tcpandas/gcc-4.8~svn195568/gcc/default/build/prev-arm-linux-gnueabi/libstdc++-v3/include
-I/cbuild/slaves/tcpandas/gcc-4.8~svn195568/gcc/gcc-4.8~svn195568/libstdc++-v3/libsupc++
-L/cbuild/slaves/tcpandas/gcc-4.8~svn195568/gcc/default/build/prev-arm-linux-gnueabi/libstdc++-v3/src/.libs
-L/cbuild/slaves/tcpandas/gcc-4.8~svn195568/gcc/default/build/prev-arm-linux-gnueabi/libstdc++-v3/libsupc++/.libs
-c   -g -O2 -gtoggle -DIN_GCC   -fno-exceptions -fno-rtti
-fasynchronous-unwind-tables -W -Wall -Wno-narrowing -Wwrite-strings
-Wcast-qual -Wmissing-format-attribute -pedantic -Wno-long-long
-Wno-variadic-macros -Wno-overlength-strings -Werror -fno-common 
-DHAVE_CONFIG_H -I. -I. -I../../../gcc-4.8~svn195568/gcc
-I../../../gcc-4.8~svn195568/gcc/. -I../../../gcc-4.8~svn195568/gcc/../include
-I../../../gcc-4.8~svn195568/gcc/../libcpp/include 
-I../../../gcc-4.8~svn195568/gcc/../libdecnumber
-I../../../gcc-4.8~svn195568/gcc/../libdecnumber/dpd -I../libdecnumber
-I../../../gcc-4.8~svn195568/gcc/../libbacktrace   
../../../gcc-4.8~svn195568/gcc/lto-streamer-out.c -o lto-streamer-out.o
../../../gcc-4.8~svn195568/gcc/lto-streamer-in.c: In function 'void
lto_input_function_body(lto_file_decl_data*, tree, const char*)':
../../../gcc-4.8~svn195568/gcc/lto-streamer-in.c:1003:1: internal compiler
error: in push_reload, at reload.c:1014
 }
 ^
0x6d1a41 push_reload(rtx_def*, rtx_def*, rtx_def**, rtx_def**, reg_class,
machine_mode, machine_mode, int, int, int, reload_type)
    ../../../gcc-4.8~svn195568/gcc/reload.c:1012
0x6daa8d find_reloads(rtx_def*, int, int, int, short*)
    ../../../gcc-4.8~svn195568/gcc/reload.c:4099
0x6e6d8b calculate_needs_all_insns
    ../../../gcc-4.8~svn195568/gcc/reload1.c:1520
0x6e560b reload(rtx_def*, int)
    ../../../gcc-4.8~svn195568/gcc/reload1.c:941
0x5f1843 do_reload
    ../../../gcc-4.8~svn195568/gcc/ira.c:4635
0x5f1a33 rest_of_handle_reload
    ../../../gcc-4.8~svn195568/gcc/ira.c:4736
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.
make[7]: *** [lto-streamer-in.o] Error 1


GCC has been configured as follows:

--prefix=/cbuild/slaves/tcpandas/gcc-4.8~svn195568/gcc/default/install
--enable-languages=c,c++,objc,obj-c++,fortran,lto --enable-linker-build-id
--with-mode=thumb --with-arch=armv7-a --with-tune=cortex-a9 --with-fpu=neon
--with-float=softfp --build=arm-linux-gnueabi


Attached test case is a reduced version which triggers the same problem with a
cross-compiler configured as:

Configured with: /work/sources/gcc-fsf/master/configure
--target=arm-none-linux-gnueabi --prefix=/work/builds/gcc-fsf-master/tools
--with-sysroot=/work/builds/gcc-fsf-master/sysroot-arm-none-linux-gnueabi
--disable-libssp --disable-libgomp --disable-libmudflap
--enable-languages=c,c++ --with-arch=armv7-a --with-fpu=vfpv3-d16
--with-float=softfp --with-thumb

Attached test case invoked by:

.../arm-none-linux-gnueabi-g++  -c    -O2 -mthumb -march=armv7-a -mfpu=neon
-mfloat-abi=softfp -mtune=cortex-a9 test.ii

Bisecting suggests the issue was introduced by subversion revision 194558:

    2012-12-17  Andrew Stubbs  <ams@codesourcery.com>
            Ulrich Weigand  <ulrich.weigand@linaro.org>

        gcc/
        * config/arm/arm.md (zero_extend<mode>di2): Add extra alternatives
        for NEON registers.
        Add alternative for one-instruction extend-in-place.
        (extend<mode>di2): Likewise.
        Add constraints for Thumb-mode memory loads.
        Prevent extend splitters doing NEON alternatives.
        * config/arm/iterators.md (qhs_extenddi_cstr, qhs_zextenddi_cstr):
        Adjust constraints to add new alternatives.
        * config/arm/neon.md: Add splitters for zero- and sign-extend.

        gcc/testsuite/
        * gcc.target/arm/neon-extend-1.c: New file.
        * gcc.target/arm/neon-extend-2.c: New file.

[Bug target/56184] [4.8 Regression] Internal compiler error in push_reload during bootstrap stage 2

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56184

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.8.0
            Summary|Internal compiler error in  |[4.8 Regression] Internal
                   |push_reload during          |compiler error in
                   |bootstrap stage 2           |push_reload during
                   |                            |bootstrap stage 2

[Bug target/56184] [4.8 Regression] Internal compiler error in push_reload during bootstrap stage 2

[mgretton at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56184

mgretton at gcc dot gnu.org changed:

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

--- Comment #1 from mgretton at gcc dot gnu.org 2013-02-05 13:08:48 UTC ---
I can reproduce this is in a compiler targeted for arm-none-eabi (and without
needing libraries built) as follows:

Compiler configured with: /work/sources/gcc-fsf/master/configure
--target=arm-none-eabi --prefix=/work/builds/gcc-fsf-master/tools
--without-headers --with-newlib --disable-shared --disable-threads
--disable-libssp --disable-libgomp --disable-libmudflap --disable-libatomic
--without-libquadmath --disable-libquadmath --enable-languages=c,c++


./cc1plus -fpreprocessed test.ii -mthumb -march=armv7-a -mfpu=neon
-mfloat-abi=softfp -mtune=cortex-a9 -O2 -o /tmp/tmp.s

RTL dumps of 208r.ira and 208r.reload are attached from running the above
command.

The assert producing the ICE is:

      int regno = REGNO (out);
      gcc_assert (regno < FIRST_PSEUDO_REGISTER
          || reg_renumber[regno] >= 0
          || reg_equiv_constant (regno) == NULL_RTX);

out: (reg:DI 358 [315])
regno: 358
reg_renumber[regno] = -1
reg_equiv_constant (regno) = ? (Can't get GDB to print the value)

[Bug target/56184] [4.8 Regression] Internal compiler error in push_reload during bootstrap stage 2

[mgretton at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56184

--- Comment #2 from mgretton at gcc dot gnu.org 2013-02-05 13:11:33 UTC ---
Created attachment 29357
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=29357
RTL dump from IRA phase

[Bug target/56184] [4.8 Regression] Internal compiler error in push_reload during bootstrap stage 2

[mgretton at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56184

--- Comment #3 from mgretton at gcc dot gnu.org 2013-02-05 13:12:18 UTC ---
Created attachment 29358
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=29358
RTL dump from reload phase

[Bug target/56184] [4.8 Regression] Internal compiler error in push_reload during bootstrap stage 2

[uweigand at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56184

Ulrich Weigand <uweigand at gcc dot gnu.org> changed:

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

--- Comment #4 from Ulrich Weigand <uweigand at gcc dot gnu.org> 2013-02-05 13:51:24 UTC ---
This is weird; I cannot reproduce the behaviour even with the exact configure
and command lines you specify.  I've been using SVN rev. 195717; which revision
do you see the problem with?

In the generated test.ii.208r.ira file I get, I see different register uses
even before IRA, compared to your version.

Would you mind sending me (offline) a full set of the dump files so I can see
where my compile run starts to diverge from yours?

[Bug target/56184] [4.8 Regression] Internal compiler error in push_reload during bootstrap stage 2

[uweigand at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56184

--- Comment #5 from Ulrich Weigand <uweigand at gcc dot gnu.org> 2013-02-06 19:27:31 UTC ---
Depending on configure tests of the installed (cross-)assembler, the ICE may
not occur.  In those cases, I'm now able to reliably reproduce the ICE by using
-fno-section-anchors (in addition to the flags given above).

[Bug target/56184] [4.8 Regression] Internal compiler error in push_reload during bootstrap stage 2

[uweigand at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56184

Ulrich Weigand <uweigand at gcc dot gnu.org> changed:

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

--- Comment #6 from Ulrich Weigand <uweigand at gcc dot gnu.org> 2013-02-06 19:40:30 UTC ---
The problem occurs with the following insn:

(insn 539 383 384 46
 (set (reg:DI 355 [313]) (const_int 256 [0x100]))
 test.ii:128 643 {*movdi_vfp}
 (expr_list:REG_EQUIV (const_int 256 [0x100])
 (nil)))

Register 355 is recognized as always-equal to the constant 256, and insn 539 is
the insn that originally sets up the equivalence.  If the register doesn't get
a hard reg, what ought to happen is that users of reg 355 get replaced by the
constant, and the insn setting the equivalence ought to be deleted.  Because
the insn will get deleted anyway, it also ought to be skipped for find_reloads.

To achieve that, reg_equiv_constant(355) should hold the constant, and
reg_equiv_init(355) should point to the above insn.  However, what actually
happens in this test case is that reg_equiv_init(355) is NULL.  Therefore, the
insn is *not* skipped for find_reloads, which then aborts since it tries to
push an output reload for an always-constant register, which is not supposed to
happen.

Now the register is somewhat special in that it was created by IRA via live
range splitting.  The original register was reg 313; and this still has
reg_equiv_init(313) pointing to the above insn.  However, reg_equiv_init(355)
is NULL.  There is a routine fix_reg_equiv_init in ira.c which appears to be
intended to fix the reg_equiv_init settings of new registers created by live
range splitting.  However, this doesn't seem to have worked in this case ...

Unfortunately I'm not really familiar with the live range splitting code; maybe
Vladimir can help with this?

[Bug target/56184] [4.8 Regression] Internal compiler error in push_reload during bootstrap stage 2

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56184

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P1

[Bug target/56184] [4.8 Regression] Internal compiler error in push_reload during bootstrap stage 2

[steven at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56184

Steven Bosscher <steven at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-checking
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2013-02-10
     Ever Confirmed|0                           |1

[Bug target/56184] [4.8 Regression] Internal compiler error in push_reload during bootstrap stage 2

[vmakarov at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56184

--- Comment #7 from Vladimir Makarov <vmakarov at gcc dot gnu.org> 2013-02-13 15:15:14 UTC ---
(In reply to comment #6)
> 
> Unfortunately I'm not really familiar with the live range splitting code; maybe
> Vladimir can help with this?

Yes, Ulrich.  I've started to work on this.

[Bug target/56184] [4.8 Regression] Internal compiler error in push_reload during bootstrap stage 2

[vmakarov at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56184

--- Comment #8 from Vladimir Makarov <vmakarov at gcc dot gnu.org> 2013-02-13 17:40:33 UTC ---
Author: vmakarov
Date: Wed Feb 13 17:40:22 2013
New Revision: 196019

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=196019
Log:
2013-02-13  Vladimir Makarov  <vmakarov@redhat.com>

    PR target/56184
    * ira.c (max_regno_before_ira): Move from ...
    (ira): ... here.
    (fix_reg_equiv_init): Use max_regno_before_ira instead of
    vec_safe_length.

2013-02-13  Vladimir Makarov  <vmakarov@redhat.com>

    PR target/56184
    * gcc.target/arm/pr56184.C: New test.


Added:
    trunk/gcc/testsuite/gcc.target/arm/pr56184.C
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/ira.c
    trunk/gcc/testsuite/ChangeLog

[Bug target/56184] [4.8 Regression] Internal compiler error in push_reload during bootstrap stage 2

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56184

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 #9 from Jakub Jelinek <jakub at gcc dot gnu.org> 2013-02-14 00:16:19 UTC ---
Fixed.