[llvm][MIRVRegNamerUtils] Adding hashing on FrameIndex MachineOperands.

This patch makes it so that cases where multiple instructions that differ only
in their FrameIndex MachineOperand values no longer collide. For instance:

%1:_(p0) = G_FRAME_INDEX %stack.0
%2:_(p0) = G_FRAME_INDEX %stack.1

Prior to this patch these instructions would collide together.

Differential Revision: https://reviews.llvm.org/D71583
diff --git a/llvm/lib/CodeGen/MIRVRegNamerUtils.cpp b/llvm/lib/CodeGen/MIRVRegNamerUtils.cpp
index d0670dc..fcc40b2 100644
--- a/llvm/lib/CodeGen/MIRVRegNamerUtils.cpp
+++ b/llvm/lib/CodeGen/MIRVRegNamerUtils.cpp
@@ -68,6 +68,8 @@
       return MO.getImm();
     case MachineOperand::MO_TargetIndex:
       return MO.getOffset() | (MO.getTargetFlags() << 16);
+    case MachineOperand::MO_FrameIndex:
+      return llvm::hash_value(MO);
 
     // We could explicitly handle all the types of the MachineOperand,
     // here but we can just return a common number until we find a
@@ -77,7 +79,6 @@
 
     // TODO: Handle the following Index/ID/Predicate cases. They can
     // be hashed on in a stable manner.
-    case MachineOperand::MO_FrameIndex:
     case MachineOperand::MO_ConstantPoolIndex:
     case MachineOperand::MO_JumpTableIndex:
     case MachineOperand::MO_CFIIndex: