[SystemZ] Fix caller-allocated save slot FIXME

Get rid of some old code (and associated FIXME) for handling the
caller-allocated register save area.  No behavioural change intended.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185525 91177308-0d34-0410-b5e6-96231b3b80d8
[SystemZ] Rename mapping table fields

Rename Function->DispKey and PairType->DispSize.  I'd originally used
"Function" because I thought it might be useful for other InstMappings.
However, it turns out that having two very similar instructions with the
same Function makes it pretty useless for anything other than the displacement
size key.  Other InstMappings will want the key to be defined for only one
instruction in the pair.

No behavioural change intended.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185526 91177308-0d34-0410-b5e6-96231b3b80d8
ARM: relax the atomic release barrier to "dmb ishst" on Swift

Swift cores implement store barriers that are stronger than the ARM
specification but weaker than general barriers. They are, in fact, just about
enough to provide the ordering needed for atomic operations with release
semantics.

This patch makes use of that quirk.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185527 91177308-0d34-0410-b5e6-96231b3b80d8
This  corrects the implementation of Thumb ADR instruction. There are three issues:
1. it should accept only 4-byte aligned addresses
2. the maximum offset should be 1020
3. it should be encoded with the offset scaled by two bits


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185528 91177308-0d34-0410-b5e6-96231b3b80d8