[Bug middle-end/43631] var-tracking inserts notes with non-NULL BLOCK_FOR_INSN in between basic blocks

["izamyatin at gmail dot com" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43631

Igor Zamyatin <izamyatin at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |izamyatin at gmail dot com

--- Comment #9 from Igor Zamyatin <izamyatin at gmail dot com> 2012-12-07 10:11:28 UTC ---
Fix led to bootstrap failure with --with-arch=core2 --with-cpu=atom flags. It
happens for
/export/gnu/import/git/gcc-test-ia32/bld/./gcc/xgcc -shared-libgcc
-B/export/gnu/import/git/gcc-test-ia32/bld/./gcc -nostdinc++
-L/export/gnu/import/git/gcc-test-ia32/bld/i686-linux/libstdc++-v3/src
-L/export/gnu/import/git/gcc-test-ia32/bld/i686-linux/libstdc++-v3/src/.libs
-B/usr/local/i686-linux/bin/ -B/usr/local/i686-linux/lib/ -isystem
/usr/local/i686-linux/include -isystem /usr/local/i686-linux/sys-include
-I/export/gnu/import/git/gcc-test-ia32/src-trunk/libstdc++-v3/../libgcc
-I/export/gnu/import/git/gcc-test-ia32/bld/i686-linux/libstdc++-v3/include/i686-linux
-I/export/gnu/import/git/gcc-test-ia32/bld/i686-linux/libstdc++-v3/include
-I/export/gnu/import/git/gcc-test-ia32/src-trunk/libstdc++-v3/libsupc++
-D_GLIBCXX_SHARED -Wall -Wextra -Wwrite-strings -Wcast-qual -Wabi
-fdiagnostics-show-location=once -ffunction-sections -fdata-sections
-frandom-seed=eh_personality.lo -g -O2 -D_GNU_SOURCE -c
../../../../src-trunk/libstdc++-v3/libsupc++/eh_personality.cc  -fPIC -DPIC
-D_GLIBCXX_SHARED -o eh_personality.o

Stack is

0x8b290da distance_non_agu_define_in_bb
    ../../src-trunk/gcc/config/i386/i386.c:16945
0x8b2928f distance_non_agu_define
    ../../src-trunk/gcc/config/i386/i386.c:17003
0x8b2968f ix86_lea_outperforms
    ../../src-trunk/gcc/config/i386/i386.c:17169
0x8b29994 ix86_use_lea_for_mov(rtx_def*, rtx_def**)
    ../../src-trunk/gcc/config/i386/i386.c:17279
0x8c5704c output_78
    ../../src-trunk/gcc/config/i386/i386.md:2191
0x85a6ae7 get_insn_template(int, rtx_def*)
    ../../src-trunk/gcc/final.c:1939
0x85a7ee0 final_scan_insn(rtx_def*, _IO_FILE*, int, int, int*)
    ../../src-trunk/gcc/final.c:2792
0x85a69b1 final(rtx_def*, _IO_FILE*, int)
    ../../src-trunk/gcc/final.c:1908
0x85aa397 rest_of_handle_final
    ../../src-trunk/gcc/final.c:4271
Please submit a full bug report,

Looks like there is some garbage in BLOCK_FOR_INSN field for barrier
instruction...