[Bug c++/82107] New: O2 optimisation on amd64 leads to error

[loquens at yandex dot ru]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82107

            Bug ID: 82107
           Summary: O2 optimisation on amd64 leads to error
           Product: gcc
           Version: 6.3.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: loquens at yandex dot ru
  Target Milestone: ---

Created attachment 42129
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=42129&action=edit
full error example sources

Complete source code attached.

Steps to reproduce this bug in amd64-environment:
 * extract archive contents
 * enter directory optfail
 * call make
 * run ./optimization_fail - program will hang

Please see comments marked "IMPORTANT" in sources and Makefile. All theese
notes change behaviour (error dissapears).

Originally found on GCC-6.3.0 compiled from sources, but 7.0.1 (from Ubuntu
17.04 repos, full version shown below) and 7.2.0 (compiled from sources, same
flags as 6.3.0, shown below) also produce error.

$ lsb_release -a
LSB Version:   
core-9.20160110ubuntu5-amd64:core-9.20160110ubuntu5-noarch:security-9.20160110ubuntu5-amd64:security-9.20160110ubuntu5-noarch
Distributor ID: Ubuntu
Description:    Ubuntu 17.04
Release:    17.04
Codename:   zesty
$ g++ --version
g++ (Ubuntu 7-20170407-0ubuntu2) 7.0.1 20170407 (experimental) [trunk revision
246759]
Copyright (C) 2017 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.


gcc-7.2.0 compilation flags:
./configure --disable-cloog-version-check \
    --disable-ppl-version-check --enable-cloog-backend=isl \
    --enable-gold --enable-languages=c,c++ --enable-lto --enable-libssp \
    --prefix=/install/prefix --with-cloog=/install/prefix \
    --with-gmp=/install/prefix --with-mlgmp=/install/prefix \
    --with-mpc=/install/prefix --with-mpfr=/install/prefix \
    --with-ppl=/install/prefix

With best regards,
loquens