Print symbolic SubRegIndex names on machine operands.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104628 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/MachineInstr.cpp b/lib/CodeGen/MachineInstr.cpp
index 06499db..e54cd5c 100644
--- a/lib/CodeGen/MachineInstr.cpp
+++ b/lib/CodeGen/MachineInstr.cpp
@@ -219,8 +219,12 @@
         OS << "%physreg" << getReg();
     }
 
-    if (getSubReg() != 0)
-      OS << ':' << getSubReg();
+    if (getSubReg() != 0) {
+      if (TM)
+        OS << ':' << TM->getRegisterInfo()->getSubRegIndexName(getSubReg());
+      else
+        OS << ':' << getSubReg();
+    }
 
     if (isDef() || isKill() || isDead() || isImplicit() || isUndef() ||
         isEarlyClobber()) {