Index: llvm/lib/CodeGen/RegisterCoalescer.cpp
===================================================================
--- llvm/lib/CodeGen/RegisterCoalescer.cpp
+++ llvm/lib/CodeGen/RegisterCoalescer.cpp
@@ -4129,6 +4129,14 @@
   else
     JoinGlobalCopies = (EnableGlobalCopies == cl::BOU_TRUE);
 
+  // FIXME: MachineFunctionProperties cannot express the required pre-property
+  // no-SSA. When running a MIR testcase without any virtual register defs, the
+  // MIR parser assumes SSA. MachineFunctionPass::getClearedProperties is called
+  // after the pass is run, so the properties at this point say it's an SSA
+  // function.  Forcibly clear it here so -verify-coalescing doesn't complain
+  // after multiple virtual register defs are introduced.
+  MRI->leaveSSA();
+
   // If there are PHIs tracked by debug-info, they will need updating during
   // coalescing. Build an index of those PHIs to ease updating.
   SlotIndexes *Slots = LIS->getSlotIndexes();