[Bug target/65682] New: bootstrap failure of gcc-4.9.2 on mips64el target in libgcc "_mulvdi3.o"

[xuchenghua at loongson dot cn]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65682

            Bug ID: 65682
           Summary: bootstrap failure of gcc-4.9.2 on mips64el target in
                    libgcc "_mulvdi3.o"
           Product: gcc
           Version: 4.9.2
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: xuchenghua at loongson dot cn

Created attachment 35243
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=35243&action=edit
the *.i file of error file.

os: Centos6.4
version: gcc-4.9.2 release version(just down from gnu, no modify).

the error message:

/home/xuchenghua/GCC/gcc-4.9.2-release_obj/./gcc/xgcc
-B/home/xuchenghua/GCC/gcc-4.9.2-release_obj/./gcc/
-B/opt/gcc-4.9.2/mips64el-redhat-linux/bin/
-B/opt/gcc-4.9.2/mips64el-redhat-linux/lib/ -isystem
/opt/gcc-4.9.2/mips64el-redhat-linux/include -isystem
/opt/gcc-4.9.2/mips64el-redhat-linux/sys-include    -g -O2 -minterlink-mips16
-mabi=32 -O2  -g -O2 -minterlink-mips16 -DIN_GCC    -W -Wall -Wwrite-strings
-Wcast-qual -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition 
-isystem ./include   -fPIC -g -DIN_LIBGCC2 -fbuilding-libgcc
-fno-stack-protector   -fPIC -I. -I. -I../../.././gcc
-I../../../../gcc-4.9.2-release/libgcc -I../../../../gcc-4.9.2-release/libgcc/.
-I../../../../gcc-4.9.2-release/libgcc/../gcc
-I../../../../gcc-4.9.2-release/libgcc/../include  -DHAVE_CC_TLS  -o _mulvdi3.o
-MT _mulvdi3.o -MD -MP -MF _mulvdi3.dep -DL_mulvdi3 -c
../../../../gcc-4.9.2-release/libgcc/libgcc2.c -fvisibility=hidden
-DHIDE_EXPORTS
../../../../gcc-4.9.2-release/libgcc/libgcc2.c: In function ‘__mulvdi3’:
../../../../gcc-4.9.2-release/libgcc/libgcc2.c:395:1: warning: ‘vn_top.0’ may
be used uninitialized in this function [-Wmaybe-uninitialized]
 }
 ^
../../../../gcc-4.9.2-release/libgcc/libgcc2.c:303:12: internal compiler error:
in int_mode_for_mode, at stor-layout.c:395
      w1.ll -= vv.ll;
            ^ 
...
...
...

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[4]: *** [_mulvdi3.o] Error 1
make[4]: Leaving directory
`/home/xuchenghua/GCC/gcc-4.9.2-release_obj/mips64el-redhat-linux/32/libgcc'
make[3]: *** [multi-do] Error 1
make[3]: Leaving directory
`/home/xuchenghua/GCC/gcc-4.9.2-release_obj/mips64el-redhat-linux/libgcc'
make[2]: *** [all-multi] Error 2
make[2]: Leaving directory
`/home/xuchenghua/GCC/gcc-4.9.2-release_obj/mips64el-redhat-linux/libgcc'
make[1]: *** [all-target-libgcc] Error 2
make[1]: Leaving directory `/home/xuchenghua/GCC/gcc-4.9.2-release_obj'
make: *** [all] Error 2

the config.log:

$ head config.log

This file contains any messages produced by compilers while
running configure, to aid debugging if configure makes a mistake.

It was created by configure, which was
generated by GNU Autoconf 2.64.  Invocation command line was

  $ ../gcc-4.9.2-release/configure --prefix=/opt/gcc-4.9.2
--with-gmp=/opt/library64/ --with-mpfr=/opt/library64/
--with-mpc=/opt/library64/ --with-cloog=/opt/library64/ --with-system-zlib
--enable-threads=posix --enable-shared --enable-long-long
--enable--disable-libjava-multilib --disable-ssp --disable-libssp
--with-local-prefix=/opt/gcc-4.9.2 --disable-bootstrap --with-abi=64
--enable-multilib --enable-languages=c,c++,fortran --host=mips64el-redhat-linux
--b
uild=mips64el-redhat-linux --target=mips64el-redhat-linux

## --------- ##
## Platform. ##


compiler command line:

 /home/xuchenghua/GCC/gcc-4.9.2-release_obj/./gcc/cc1 -fpreprocessed libgcc2.i
-mel -quiet -dumpbase libgcc2.c -mabi=32 -minterlink-mips16 -mllsc
-auxbase-strip _mulvdi3.o -g -g -g -O2 -O2 -O2 -Wextra -Wall -Wwrite-strings
-Wcast-qual -Wstrict-prototypes -Wmissing-prototypes -Wold-style-definition
-version -fbuilding-libgcc -fno-stack-protector -fPIC -fvisibility=hidden -o
libgcc2.s