[IR] Add bounds checking to paramHasAttr

Summary:
This is intended to make a later change simpler.

Note: adding this bounds checking required fixing `X86FastISel`.  As
far I can tell I've preserved original behavior but a careful review
will be appreciated.

Reviewers: reames

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D14304

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252073 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed