opt: Initialize asm printers

Without initializing the assembly printers a shared library build of opt is
linked with these libraries whereas for a static build these libraries are dead
code eliminated. This is unfortunate for plugins in case they want to use them,
as they neither can rely on opt to provide this functionality nor can they link
the printers in themselves as this breaks with a shared object build of opt.

This patch calls InitializeAllAsmPrinters() from opt, which increases the static
binary size from 50MB -> 52MB on my system (all backends compiled) and causes no
measurable increase in the time needed to run 'make check'.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210914 91177308-0d34-0410-b5e6-96231b3b80d8
R600: Remove AMDIL instruction and register definitions

Most of these are no longer used any more.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210915 91177308-0d34-0410-b5e6-96231b3b80d8
Atomics: switch direction of cmpxchg comparison

This has two benefits: it makes the result more suitable for direct
insertaion into the struct to emulate the new cmpxchg, and it means
the name we give the instruction matches its actual effect better.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210916 91177308-0d34-0410-b5e6-96231b3b80d8
Atomics: make use of the "cmpxchg weak" instruction.

This also simplifies the IR we create slightly: instead of working out
where success & failure should go manually, it turns out we can just
always jump to a success/failure block created for the purpose. Later
phases will sort out the mess without much difficulty.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@210917 91177308-0d34-0410-b5e6-96231b3b80d8