[Bug target/71009] g++: ICE on modified gdb/valarith.c with -Ofast

[egall at gwmail dot gwu.edu]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71009

--- Comment #3 from Eric Gallager <egall at gwmail dot gwu.edu> ---
Still happens with:

$ /usr/local/bin/g++ -v
Using built-in specs.
COLLECT_GCC=/usr/local/bin/g++
COLLECT_LTO_WRAPPER=/usr/local/libexec/gcc/i386-apple-darwin9.8.0/7.0.0/lto-wrapper
Target: i386-apple-darwin9.8.0
Configured with: ../configure --disable-werror
--enable-languages=c,c++,lto,objc,obj-c++ --enable-stage1-checking=release -C
--with-system-libunwind --enable-secureplt --enable-frame-pointer
--enable-debug --without-isl --enable-objc-gc --enable-host-shared
CC=/usr/local/bin/gcc CXX=/usr/local/bin/g++
Thread model: posix
gcc version 7.0.0 20160526 (experimental) (GCC) 


This time I attached gdb and got a backtrace:

(gdb) bt
#0  0x00ed6004 in internal_error ()
#1  0x00ed5040 in fancy_abort ()
#2  0x00719077 in gen_reg_rtx ()
#3  0x0048fc28 in gen_split_343 ()
#4  0x00569b62 in split_8 ()
#5  0x00720956 in try_split ()
#6  0x00a6a7be in split_insn ()
#7  0x00a6ec9a in split_all_insns ()
#8  0x00a6ecfb in (anonymous namespace)::pass_split_after_reload::execute ()
#9  0x00a3c567 in execute_one_pass ()
#10 0x00a3cb59 in execute_pass_list_1 ()
#11 0x00a3cb6c in execute_pass_list_1 ()
#12 0x00a3cb6c in execute_pass_list_1 ()
#13 0x00a3cbba in execute_pass_list ()
#14 0x0063b7d9 in cgraph_node::expand ()
#15 0x0063d244 in symbol_table::compile ()
#16 0x0063f74d in symbol_table::finalize_compilation_unit ()
#17 0x00b19b51 in compile_file ()
#18 0x0177f168 in toplev::main ()
#19 0x01780a24 in main ()

I'll have to rebuild gcc for debugging to get further info.