[llvm-bugs] [Bug 51883] New: Undefined Reference to static constexpr when compiling with -fprofile-instr-generate

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=51883

            Bug ID: 51883
           Summary: Undefined Reference to static constexpr when compiling
                    with -fprofile-instr-generate
           Product: clang
           Version: trunk
          Hardware: PC
                OS: Linux
            Status: NEW
          Severity: normal
          Priority: P
         Component: C++14
          Assignee: unassignedclangbugs at nondot.org
          Reporter: thoren.paulson at gmail.com
                CC: blitzrakete at gmail.com, erik.pilkington at gmail.com,
                    llvm-bugs at lists.llvm.org, richard-llvm at metafoo.co.uk

Godbolt link: https://godbolt.org/z/vqEjKEKch

When I compile the following code with `-Oz -std=c++14
-fprofile-instr-generate`, it refers to the undefined symbol kUndefined, which
causes "undefined reference" at link time.

```
#include <algorithm>


class Foo {
private:
    static constexpr int kUndefined = 4;
public:
    int Bar(int a);
};

int Foo::Bar(int a) {
    return std::max(a, kUndefined);
}
```

It seems this is because std::max takes its arguments by reference, so if it
doesn't get inlined (consequence of -Oz), code is generated referring to
kUndefined, but there is no code generated to define kUndefined.

-- 
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/20210916/bb500d9f/attachment.html>