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From: "derek.mauro at gmail dot com" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug c++/96188] New: -Wstringop-overflow false positive
Date: Mon, 13 Jul 2020 15:51:49 +0000
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X-Bugzilla-Product: gcc
X-Bugzilla-Component: c++
X-Bugzilla-Version: 10.1.0
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D96188

            Bug ID: 96188
           Summary: -Wstringop-overflow false positive
           Product: gcc
           Version: 10.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: derek.mauro at gmail dot com
  Target Milestone: ---

This is strange issue that started appearing in gcc 10.1. It also seems to
require -O3 and -std=3Dgnu++11 (gnu++14 etc appear unaffected).

Godbolt demo: https://godbolt.org/z/W8MWbz

Test case copy/pasted below.

Use -Werror -Wstringop-overflow -std=3Dgnu++11 -O3

#include <string>
#include <vector>

bool b;

void F() {
  static bool b2 =3D b;
  for (const int fx : {0}) {
    struct Expectation {
      std::string out;
    };

    std::vector<Expectation> expect =3D {
        {std::string()},
        {std::string()},
        {std::string()},
    };
    if (b2) {
      expect.push_back({std::string()});
    }

  }
}=