Add two helpers to IRBuilder to flesh the interface out to N-width
integers. Complements the interfaces it is wrapping.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202251 91177308-0d34-0410-b5e6-96231b3b80d8
[SROA] Use the correct index integer size in GEPs through non-default
address spaces.

This isn't really a correctness issue (the values are truncated) but its
much cleaner.

Patch by Matt Arsenault!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202252 91177308-0d34-0410-b5e6-96231b3b80d8
[mips] Treat -mcpu=generic the same way as an empty CPU string.

Summary:
This should fix the MCJIT unit tests that were broken by r201792 on the MIPS buildbot.
MIPS currently uses the default implementation of sys::getHostCPUName() which
always returns "generic". For now, we will accept "generic" and coerce it to
"mips32" or "mips64" depending on the target architecture like we do for empty
CPU names.

Reviewers: jacksprat, matheusalmeida

Reviewed By: jacksprat

Differential Revision: http://llvm-reviews.chandlerc.com/D2878

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@202253 91177308-0d34-0410-b5e6-96231b3b80d8