CodeGen: improve MachineInstrBuilder & MachineIRBuilder interface
For MachineInstrBuilder, having to manually use RegState::Define is ugly and
makes register definitions clunkier than they need to be, so this adds two
convenience functions: addDef and addUse.
For MachineIRBuilder, we want to avoid BuildMI's first-reg-is-def rule because
it's hidden away and causes bugs. So this patch switches buildInstr to
returning a MachineInstrBuilder and adding *all* operands via addDef/addUse.
NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@277176
91177308-0d34-0410-b5e6-
96231b3b80d8