[Bug libstdc++/77413] New: [7 regression] experimental/numeric/gcd.cc etc. FAIL

["ro at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77413

            Bug ID: 77413
           Summary: [7 regression] experimental/numeric/gcd.cc etc. FAIL
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: ro at gcc dot gnu.org
                CC: redi at gcc dot gnu.org
  Target Milestone: ---
              Host: *-*-solaris2.12
            Target: *-*-solaris2.12
             Build: *-*-solaris2.12

Between 20160826 (r239769) and 20610829 (r239817), two new testsuite
regressions
occured on Solaris 12 (haven't tried earlier OS versions yet):

+FAIL: experimental/numeric/gcd.cc (test for excess errors)

Excess errors:
/vol/gcc/src/hg/trunk/local/libstdc++-v3/testsuite/experimental/numeric/gcd.cc:24:
error: non-constant condition for static assertion
/vol/gcc/src/hg/trunk/local/libstdc++-v3/testsuite/experimental/numeric/gcd.cc:24:
  in constexpr expansion of 'std::experimental::fundamentals_v2::lcm<int,
int>(21, 6)'
/var/gcc/regression/trunk/12-gcc/build/i386-pc-solaris2.12/libstdc++-v3/include/experimental/numeric:77:
error: call to non-constexpr function 'int std::abs(int)'

+FAIL: experimental/numeric/lcm.cc (test for excess errors)

Excess errors:
/vol/gcc/src/hg/trunk/local/libstdc++-v3/testsuite/experimental/numeric/lcm.cc:24:
error: non-constant condition for static assertion
/vol/gcc/src/hg/trunk/local/libstdc++-v3/testsuite/experimental/numeric/lcm.cc:24:
  in constexpr expansion of 'std::experimental::fundamentals_v2::gcd<int,
int>(1071, 462)'
/var/gcc/regression/trunk/12-gcc/build/i386-pc-solaris2.12/libstdc++-v3/include/experimental/numeric:65:
  in constexpr expansion of 'std::experimental::fundamentals_v2::gcd<int,
int>(__n, (__m % __n))'
/var/gcc/regression/trunk/12-gcc/build/i386-pc-solaris2.12/libstdc++-v3/include/experimental/numeric:65:
  in constexpr expansion of 'std::experimental::fundamentals_v2::gcd<int,
int>(__n, (__m % __n))'
/var/gcc/regression/trunk/12-gcc/build/i386-pc-solaris2.12/libstdc++-v3/include/experimental/numeric:65:
  in constexpr expansion of 'std::experimental::fundamentals_v2::gcd<int,
int>(__n, (__m % __n))'
/var/gcc/regression/trunk/12-gcc/build/i386-pc-solaris2.12/libstdc++-v3/include/experimental/numeric:64:
error: call to non-constexpr function 'int std::abs(int)'
/vol/gcc/src/hg/trunk/local/libstdc++-v3/testsuite/experimental/numeric/lcm.cc:25:
error: non-constant condition for static assertion
/vol/gcc/src/hg/trunk/local/libstdc++-v3/testsuite/experimental/numeric/lcm.cc:25:
  in constexpr expansion of 'std::experimental::fundamentals_v2::gcd<int,
int>(2000, 20)'
/var/gcc/regression/trunk/12-gcc/build/i386-pc-solaris2.12/libstdc++-v3/include/experimental/numeric:65:
  in constexpr expansion of 'std::experimental::fundamentals_v2::gcd<int,
int>(__n, (__m % __n))'
/var/gcc/regression/trunk/12-gcc/build/i386-pc-solaris2.12/libstdc++-v3/include/experimental/numeric:64:
error: call to non-constexpr function 'int std::abs(int)'
/vol/gcc/src/hg/trunk/local/libstdc++-v3/testsuite/experimental/numeric/lcm.cc:26:
error: non-constant condition for static assertion
/vol/gcc/src/hg/trunk/local/libstdc++-v3/testsuite/experimental/numeric/lcm.cc:26:
  in constexpr expansion of 'std::experimental::fundamentals_v2::gcd<int,
int>(2011, 17)'

both 32 and 64-bit, both sparc and x86.

I noticed that the earlier (successful) test was compiled without -include
bits/stdc++.h, while the newer (failing) one is using that flag.  Omitting it
manually lets the tests PASS.

I suspect this is from testsuite/lib/libstdc++.exp (libstdc++_init), but
haven't checked yet.

  Rainer