[flang] Fix .NOT. folding bug

Original-commit: flang-compiler/f18@dd4d9091f15ce3912937b9ceaac7efbbf793d0b5
Tree-same-pre-rewrite: false

diff --git a/flang/lib/evaluate/fold.cc b/flang/lib/evaluate/fold.cc
index a72853b..83ab5e5 100644 (file)
--- a/flang/lib/evaluate/fold.cc
+++ b/flang/lib/evaluate/fold.cc
@@ -507,7 +507,7 @@ Expr<Type<TypeCategory::Logical, KIND>> FoldOperation(
   auto &operand{x.left()};
   operand = Fold(context, std::move(operand));
   if (auto value{GetScalarConstantValue<Ty>(operand)}) {
-    return Expr<Ty>{Constant<Ty>{value->IsTrue()}};
+    return Expr<Ty>{Constant<Ty>{!value->IsTrue()}};
   }
   return Expr<Ty>{x};
 }