AMDGPU: Replace i64 add/sub lowering
Use VOP3 add/addc like usual.
This has some tradeoffs. Inline immediates fold
a little better, but other constants are worse off.
SIShrinkInstructions could be made smarter to handle
these cases.
This allows us to avoid selecting scalar adds where we
need to track the carry in scc and replace its users.
This makes it easier to use the carryless VALU adds.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@318340 91177308-0d34-0410-b5e6-96231b3b80d8
17 files changed