DebugInfo: Use the signedness of the underlying enum when encoding enum non-type-template-parameters

This improves the accuracy of the debug info and improves round tripping
through -gsimple-template-names.

1 files changed, 9 insertions, 8 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp b/llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp
index c957ca8..4df34d2 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DebugHandlerBase.cpp
@@ -185,14 +185,15 @@ bool DebugHandlerBase::isUnsignedDIType(const DIType *Ty) {
   }
 
   if (auto *CTy = dyn_cast<DICompositeType>(Ty)) {
-    // FIXME: Enums without a fixed underlying type have unknown signedness
-    // here, leading to incorrectly emitted constants.
-    if (CTy->getTag() == dwarf::DW_TAG_enumeration_type)
-      return false;
-
-    // (Pieces of) aggregate types that get hacked apart by SROA may be
-    // represented by a constant. Encode them as unsigned bytes.
-    return true;
+    if (CTy->getTag() == dwarf::DW_TAG_enumeration_type) {
+      if (!(Ty = CTy->getBaseType()))
+        // FIXME: Enums without a fixed underlying type have unknown signedness
+        // here, leading to incorrectly emitted constants.
+        return false;
+    } else
+      // (Pieces of) aggregate types that get hacked apart by SROA may be
+      // represented by a constant. Encode them as unsigned bytes.
+      return true;
   }
 
   if (auto *DTy = dyn_cast<DIDerivedType>(Ty)) {