[PATCH] [IR] Fix the definition of 'shl nsw'

[Sanjoy Das]

Just to be clear, you're explicitly making `shl nsw X Y` be poison less often than `mul nsw X (1<<Y)`?  The example I have in mind is (for i8) `X` = `-1`, `Y` = `7`.  If so, that might be worth stating in the LangRef, maybe even with an example or two.


http://reviews.llvm.org/D8890

EMAIL PREFERENCES
  http://reviews.llvm.org/settings/panel/emailpreferences/