[llvm-bugs] [Bug 26535] New: "tautological-undefined-compare" warning is not fired when dereferrenced null pointer is casted back to pointer

[via llvm-bugs]

https://llvm.org/bugs/show_bug.cgi?id=26535

            Bug ID: 26535
           Summary: "tautological-undefined-compare" warning is not fired
                    when dereferrenced null pointer is casted back to
                    pointer
           Product: new-bugs
           Version: 3.6
          Hardware: PC
                OS: Windows NT
            Status: NEW
          Severity: normal
          Priority: P
         Component: new bugs
          Assignee: unassignedbugs at nondot.org
          Reporter: dmitry at dali-studio.com
                CC: llvm-bugs at lists.llvm.org
    Classification: Unclassified

Here's a sample snippet:

int& get() {
     return *reinterpret_cast<int*>(0); // this code is UB
}

void test() {
int* foo = &(get());
if (foo == nullptr) { // silently optimized away, no warnings

}
}

This broke existing code while migrating from 3.4 to 3.6 (Android NDK). Yes,
the above code is UB, so a warning would be nice.

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