Delete unused argument in AArch64MCInstLower constructor: it doesn't
use Mangler, and Mangler is in fact not even created when AArch64MCInstLower
is constructed.

This bug is reported by UBSan.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216030 91177308-0d34-0410-b5e6-96231b3b80d8
Split parseAssembly into parseAssembly and parseAssemblyInto.

This should restore the functionality of parsing new code into an existing
module without the confusing interface.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216031 91177308-0d34-0410-b5e6-96231b3b80d8
[FastISel][AArch64] Factor out ADDS/SUBS instruction emission and add support for extensions and shift folding.

Factor out the ADDS/SUBS instruction emission code into helper functions and
make the helper functions more clever to support most of the different ADDS/SUBS
instructions the architecture support. This includes better immedediate support,
shift folding, and sign-/zero-extend folding.

This fixes <rdar://problem/17913111>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@216033 91177308-0d34-0410-b5e6-96231b3b80d8