rust-lang/rust — pull request #18580 by hirschenberger (2014-11-03 19:10:28+00:00)
Title: Also fix undefined behaviour when shift equals the number of bits

As @ben0x539 commented in #18206 for issie #17713

LLVM states: "If op2 is (statically or dynamically) negative or equal
to or larger than the number of bits in op1, the result is undefined."