MIR: Support MachineMemOperands without associated value

This is allowed (though used rarely) and useful to keep your tests
short.

llvm-svn: 271752
diff --git a/llvm/lib/CodeGen/MIRPrinter.cpp b/llvm/lib/CodeGen/MIRPrinter.cpp
index 95b58b7..703c99d 100644
--- a/llvm/lib/CodeGen/MIRPrinter.cpp
+++ b/llvm/lib/CodeGen/MIRPrinter.cpp
@@ -883,11 +883,12 @@
     assert(Op.isStore() && "Non load machine operand must be a store");
     OS << "store ";
   }
-  OS << Op.getSize() << (Op.isLoad() ? " from " : " into ");
+  OS << Op.getSize();
   if (const Value *Val = Op.getValue()) {
+    OS << (Op.isLoad() ? " from " : " into ");
     printIRValueReference(*Val);
-  } else {
-    const PseudoSourceValue *PVal = Op.getPseudoValue();
+  } else if (const PseudoSourceValue *PVal = Op.getPseudoValue()) {
+    OS << (Op.isLoad() ? " from " : " into ");
     assert(PVal && "Expected a pseudo source value");
     switch (PVal->kind()) {
     case PseudoSourceValue::Stack: