[DebugInfoMetadata] Refactor DIExpression::prepend constants (NFC)

Refactor DIExpression::With* into a flag enum in order to be less
error-prone to use (as discussed on D60866).

Patch by Djordje Todorovic.

Differential Revision: https://reviews.llvm.org/D61943

llvm-svn: 361137

1 files changed, 1 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/MachineInstr.cpp b/llvm/lib/CodeGen/MachineInstr.cpp
index 12091577521..be39a726140 100644
--- a/llvm/lib/CodeGen/MachineInstr.cpp
+++ b/llvm/lib/CodeGen/MachineInstr.cpp
@@ -2075,7 +2075,7 @@ static const DIExpression *computeExprForSpill(const MachineInstr &MI) {
   const DIExpression *Expr = MI.getDebugExpression();
   if (MI.isIndirectDebugValue()) {
     assert(MI.getOperand(1).getImm() == 0 && "DBG_VALUE with nonzero offset");
-    Expr = DIExpression::prepend(Expr, DIExpression::WithDeref);
+    Expr = DIExpression::prepend(Expr, DIExpression::DerefBefore);
   }
   return Expr;
 }