lowering and requires that certain types exist in ValueTypes.h. Modified widening to
check if an op can trap and if so, the widening algorithm will apply only the op on
the defined elements. It is safer to do this in widening because the optimizer can't
guarantee removing unused ops in some cases.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@95823 91177308-0d34-0410-b5e6-96231b3b80d8
