[LLVMbugs] [Bug 19534] UBSan: False positive for large left shift

[bugzilla-daemon at llvm.org]

http://llvm.org/bugs/show_bug.cgi?id=19534

Richard Smith <richard-llvm at metafoo.co.uk> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |richard-llvm at metafoo.co.uk
         Resolution|---                         |INVALID

--- Comment #1 from Richard Smith <richard-llvm at metafoo.co.uk> ---
UBSan is correct. C11 6.5.7/3 says:

"If the value of the right operand is negative or is greater than or equal to
the width of the promoted left operand, the behavior is undefined."

C++11 5.8/1 says:

"The behavior is undefined if the right operand is negative, or greater than or
equal to the length in bits of the promoted left operand."

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