https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79743
Bug ID: 79743
Summary: std::experimental::optional<boolean> constructor
broken in gcc 6.2
Product: gcc
Version: lto
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
Assignee: unassigned at gcc dot gnu.org
Reporter: krisk0.2017.02.27 at protonmail dot com
Target Milestone: ---
Created attachment 40841
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=40841&action=edit
all files mentioned in bug-report
Short story: std::experimental::optional<boolean> copy-constructor is broken
under GCC 6.2. 47-line .cpp proves it.
Long story as required by https://gcc.gnu.org/bugs/:
* the exact version of GCC
sys-devel/gcc-5.3.0 --- works fine
sys-devel/gcc-6.2.0 --- buggy
* the system type
Gentoo on amd64 (Intel Core i5)
* the options given when GCC was configured/built
See files 5.3.configure and 6.2.configure
* the complete command line that triggers the bug
Install Google test --- package dev-cpp/gtest;
g++ -std=c++14 -O2 -lgtest test.cpp && ./a.out
Test passes under gcc 5.3 and fails under 6.2.
std::experimental::optional<boolean> constructor sets butter to false though it
should be undefined.
* the compiler output (error messages, warnings)
None
* the preprocessed file (*.i*)
test.5.3.ii --- works fine, test passes
test.6.2.ii --- test fails
```
test.cpp:40: Failure
Value of: !s1.butter
Actual: false
Expected: true
test.cpp:40: Failure
Value of: Nothing
Actual: 1-byte object <00>
Expected: s1.butter
Which is: 2-byte object <00-01>
```
