https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61657
--- Comment #8 from Vittorio Zecca <zeccav at gmail dot com> --- Maybe the easiest way to reproduce the issue is as in the following; gdb ~/local/gcc-5.2.0-sanitized/libexec/gcc/x86_64-unknown-linux-gnu/5.2.0/cc1 GNU gdb (GDB) Fedora 7.8.2-39.fc21 Copyright (C) 2014 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html> This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. Type "show copying" and "show warranty" for details. This GDB was configured as "x86_64-redhat-linux-gnu". Type "show configuration" for configuration details. For bug reporting instructions, please see: <http://www.gnu.org/software/gdb/bugs/>. Find the GDB manual and other documentation resources online at: <http://www.gnu.org/software/gdb/documentation/>. For help, type "help". Type "apropos word" to search for commands related to "word"... Reading symbols from /home/vitti/local/gcc-5.2.0-sanitized/libexec/gcc/x86_64-unknown-linux-gnu/5.2.0/cc1...done. (gdb) break ../../gcc-5.2.0/gcc/loop-iv.c:2671 Breakpoint 1 at 0x153209e: file ../../gcc-5.2.0/gcc/loop-iv.c, line 2671. (gdb) run gccerr14.c -O -quiet -funroll-loops Starting program: /home/vitti/local/gcc-5.2.0-sanitized/libexec/gcc/x86_64-unknown-linux-gnu/5.2.0/cc1 gccerr14.c -O -quiet -funroll-loops Missing separate debuginfos, use: debuginfo-install glibc-2.20-8.fc21.x86_64 [Thread debugging using libthread_db enabled] Using host libthread_db library "/lib64/libthread_db.so.1". Breakpoint 1, iv_number_of_iterations (loop=0x2aaab633f360, insn=0x2aaab635e400, condition=0x2aaab6362d98, desc=0x7fffffffa810) at ../../gcc-5.2.0/gcc/loop-iv.c:2671 2671 max = (uint64_t) (up - down) / inc + 1; Missing separate debuginfos, use: debuginfo-install gmp-6.0.0-9.fc21.x86_64 libmpc-1.0.2-3.fc21.x86_64 mpfr-3.1.2-8.fc21.x86_64 (gdb) print up $1 = 7 (gdb) print down $2 = -9223372036854775808 But you need an unoptimized version of cc1
