[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, 4 insertions, 2 deletions

diff --git a/llvm/lib/CodeGen/LiveDebugVariables.cpp b/llvm/lib/CodeGen/LiveDebugVariables.cpp
index 648d3ee..c3503bd 100644
--- a/llvm/lib/CodeGen/LiveDebugVariables.cpp
+++ b/llvm/lib/CodeGen/LiveDebugVariables.cpp
@@ -1316,11 +1316,13 @@ void UserValue::insertDebugValue(MachineBasicBlock *MBB, SlotIndex StartIdx,
   // that the original virtual register was a pointer. Also, add the stack slot
   // offset for the spilled register to the expression.
   const DIExpression *Expr = Expression;
+  uint8_t DIExprFlags = DIExpression::ApplyOffset;
   bool IsIndirect = Loc.wasIndirect();
   if (Spilled) {
-    auto Deref = IsIndirect ? DIExpression::WithDeref : DIExpression::NoDeref;
+    if (IsIndirect)
+      DIExprFlags |= DIExpression::DerefAfter;
     Expr =
-        DIExpression::prepend(Expr, DIExpression::NoDeref, SpillOffset, Deref);
+        DIExpression::prepend(Expr, DIExprFlags, SpillOffset);
     IsIndirect = true;
   }