add more and significantly better comments to the rest of the machineinstr

flags that can be set.  Add predicates for the ones lacking it, and switch
some clients over to using the predicates instead of Flags directly.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@45690 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/TwoAddressInstructionPass.cpp

@@ -172,7 +172,7 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) {
 
             // If this instruction is potentially convertible to a true
             // three-address instruction,
-            if (TID->Flags & M_CONVERTIBLE_TO_3_ADDR) {
+            if (TID->isConvertibleTo3Addr()) {
               // FIXME: This assumes there are no more operands which are tied
               // to another register.
 #ifndef NDEBUG