[ConstExpr] Look through move_value insts.

Just like begin_borrow and copy_value, move_value should be looked
through because the interpreter doesn't model the memory operation it
encodes.

Author: nate-chandler

lib/SILOptimizer/Utils/ConstExpr.cpp

@@ -488,9 +488,10 @@ SymbolicValue ConstExprFunctionState::computeConstantValue(SILValue value) {
   if (auto *bai = dyn_cast<BeginAccessInst>(value))
     return getConstantValue(bai->getOperand());
 
-  // Look through copy_value and begin_borrow since the interpreter doesn't
-  // model these memory management instructions.
-  if (isa<CopyValueInst>(value) || isa<BeginBorrowInst>(value))
+  // Look through copy_value, begin_borrow, and move_value since the
+  // interpreter doesn't model these memory management instructions.
+  if (isa<CopyValueInst>(value) || isa<BeginBorrowInst>(value) ||
+      isa<MoveValueInst>(value))
     return getConstantValue(cast<SingleValueInstruction>(value)->getOperand(0));
 
   // Builtin.RawPointer and addresses have the same representation.