diff --git a/llvm/lib/CodeGen/InlineSpiller.cpp b/llvm/lib/CodeGen/InlineSpiller.cpp
--- a/llvm/lib/CodeGen/InlineSpiller.cpp
+++ b/llvm/lib/CodeGen/InlineSpiller.cpp
@@ -945,6 +945,10 @@
 /// insertSpill - Insert a spill of NewVReg after MI.
 void InlineSpiller::insertSpill(unsigned NewVReg, bool isKill,
                                  MachineBasicBlock::iterator MI) {
+  // Spill are not terminators, so inserting spills after terminators will
+  // violate invariants in MachineVerifier. This is commonly observed with
+  // -verify-machineinstrs or even -verify-regalloc.
+  assert(!MI->isTerminator() && "Inserting a spill after a terminator");
   MachineBasicBlock &MBB = *MI->getParent();
 
   MachineInstrSpan MIS(MI, &MBB);