[Bug libstdc++/77717] New: testsuite/21_strings/basic_string_view/operations/compare/char/1.cc makes undefined memcmp call

[acsawdey at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77717

            Bug ID: 77717
           Summary: testsuite/21_strings/basic_string_view/operations/comp
                    are/char/1.cc makes undefined memcmp call
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: acsawdey at gcc dot gnu.org
                CC: ville.voutilainen at gmail dot com
  Target Milestone: ---

This test case makes an undefined call to memcmp because the string constant is
shorter than the length given. "costa rica" is 11 bytes including the '\0' but
length of 14 is given. The last two lines of code quoted below both do it.

int
test01()
{
  using std::string_view;

  string_view   str_0("costa rica");
  string_view   str_1("costa marbella");
  string_view   str_2;

  //sanity check
  test_value(strcmp("costa marbella", "costa rica"), lt);
  test_value(strcmp("costa rica", "costa rica"), z);
  test_value(strcmp(str_1.data(), str_0.data()), lt);
  test_value(strcmp(str_0.data(), str_1.data()), gt);
  test_value(strncmp(str_1.data(), str_0.data(), 6), z);
  test_value(strncmp(str_1.data(), str_0.data(), 14), lt);
  test_value(memcmp(str_1.data(), str_0.data(), 6), z);
  test_value(memcmp(str_1.data(), str_0.data(), 14), lt);
  test_value(memcmp("costa marbella", "costa rica", 14), lt);