[InstructionDeleter] Add fixLifetime argument.

Clients may not want the lifetime to be fixed up.

Author: nate-chandler

include/swift/SILOptimizer/Utils/InstructionDeleter.h

@@ -159,6 +159,7 @@ class InstructionDeleter {
   ///
   /// Calls callbacks.notifyWillBeDeleted().
   bool deleteIfDead(SILInstruction *inst);
+  bool deleteIfDead(SILInstruction *inst, bool fixLifetime);
 
   /// Delete the instruction \p inst, ignoring its side effects. If any operand
   /// definitions will become dead after deleting this instruction, track them

lib/SILOptimizer/Utils/InstructionDeleter.cpp

@@ -276,6 +276,10 @@ void InstructionDeleter::cleanupDeadInstructions() {
 
 bool InstructionDeleter::deleteIfDead(SILInstruction *inst) {
   bool fixLifetime = inst->getFunction()->hasOwnership();
+  return deleteIfDead(inst, fixLifetime);
+}
+
+bool InstructionDeleter::deleteIfDead(SILInstruction *inst, bool fixLifetime) {
   if (isInstructionTriviallyDead(inst)
       || isScopeAffectingInstructionDead(inst, fixLifetime)) {
     getCallbacks().notifyWillBeDeleted(inst);