Fix unsupported addressing mode assertion for pld

Summary:
This commit gives an address mode to the PLD instruction. We
were getting an assertion failure in the frame lowering code
because we had code that was doing a pld of a stack allocated
address. The frame lowering was checking the address mode and
then asserting because pld had none defined.

This commit fixes pld for arm mode. There was a previous fix for
thumb mode in a separate commit. The commit for thumb mode
added a test in a separate file because it would otherwise fail
for arm. This commit moves the thumb test back into the prefetch.ll
file and adds the corresponding arm test.

Differential Revision: http://llvm-reviews.chandlerc.com/D2622


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200248 91177308-0d34-0410-b5e6-96231b3b80d8
Fix sext(setcc) -> select_cc using wrong type for setcc.

Also update the comment, since it actually produces a
select (setcc) instead of select_cc.

It was checking and using the setcc result type for the
type of the sext, instead of the type of the compared items.

In my problem case, the sext was to i32 and was used as the setcc type,
but the expected type was i64.

No test since I haven't been able to hit the problem with
this on any in-tree targets.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@200249 91177308-0d34-0410-b5e6-96231b3b80d8