[llvm-bugs] [Bug 34426] New: Miscompiled direct base initialization in inherited constructor from virtual base of same type

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=34426

            Bug ID: 34426
           Summary: Miscompiled direct base initialization in inherited
                    constructor from virtual base of same type
           Product: clang
           Version: trunk
          Hardware: All
                OS: All
            Status: NEW
          Keywords: miscompilation
          Severity: normal
          Priority: P
         Component: C++
          Assignee: unassignedclangbugs at nondot.org
          Reporter: hstong at ca.ibm.com
                CC: dgregor at apple.com, llvm-bugs at lists.llvm.org

When a constructor is inherited from a virtual base and the class from which
said constructor is inherited is also a direct base of the complete object
being constructed, the initialization of the direct base is supposed to be a
default initialization, but Clang seems to treat it like the virtual base.

### SOURCE (<stdin>):
extern "C" int printf(const char *, ...);

struct A { A(int); A() = default; };
A::A(int x) { printf("%s: %d\n", __PRETTY_FUNCTION__, x); }

struct B : virtual A { using A::A; };
struct C : B, A { using B::B; };

int main(void) { C c(42); }


### COMPILER INVOCATION:
clang++ -Wall -Wextra -Wno-inaccessible-base -xc++ -std=c++1z -o a.out -


### COMPILER OUTPUT:
(Clean compile)


### ACTUAL RUN OUTPUT (./a.out):
A::A(int): 42
A::A(int): 42


### EXPECTED RUN OUTPUT:
A::A(int): 42


### COMPILER VERSION INFO (clang++ -v):
clang version 6.0.0 (https://github.com/llvm-mirror/clang.git
9b13d907c509a53fd938dcc777bb7dd097cea4c0)
(https://github.com/llvm-mirror/llvm.git
707fb1cf0ca99d98c59f1ae87b7e0ff9b2dd0c8b)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /opt/wandbox/clang-head/bin
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.4.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6
Found candidate GCC installation: /usr/lib/gcc/x86_64-linux-gnu/6.0.0
Selected GCC installation: /usr/lib/gcc/x86_64-linux-gnu/5.4.0
Candidate multilib: .;@m64
Selected multilib: .;@m64

-- 
You are receiving this mail because:
You are on the CC list for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-bugs/attachments/20170902/2f36d406/attachment.html>