[SILMem2Reg] add an assert when replacing debug_value_addr with debug_value: make sure it is not an address-only type

Author: Joe Shajrawi

lib/SILOptimizer/Transforms/SILMem2Reg.cpp

@@ -277,6 +277,8 @@ bool MemoryToRegisters::isWriteOnlyAllocation(AllocStackInst *ASI) {
 /// Promote a DebugValueAddr to a DebugValue of the given value.
 static void
 promoteDebugValueAddr(DebugValueAddrInst *DVAI, SILValue Value, SILBuilder &B) {
+  assert(DVAI->getOperand()->getType().isLoadable(DVAI->getModule()) &&
+         "Unexpected promotion of address-only type!");
   assert(Value && "Expected valid value");
   B.setInsertionPoint(DVAI);
   B.setCurrentDebugScope(DVAI->getDebugScope());