[flang] Do not ICE on out-of-range data statement designator

Print error message instead of assert trigger.

Reviewed By: klausler

Differential Revision: https://reviews.llvm.org/D123132

flang/lib/Evaluate/fold-designator.cpp

@@ -298,7 +298,9 @@ static std::optional<DataRef> OffsetToDataRef(FoldingContext &context,
 // Reconstructs a Designator from a symbol, an offset, and a size.
 std::optional<Expr<SomeType>> OffsetToDesignator(FoldingContext &context,
     const Symbol &baseSymbol, ConstantSubscript offset, std::size_t size) {
-  CHECK(offset >= 0);
+  if (offset < 0) {
+    return std::nullopt;
+  }
   if (std::optional<DataRef> dataRef{
           OffsetToDataRef(context, NamedEntity{baseSymbol}, offset, size)}) {
     const Symbol &symbol{dataRef->GetLastSymbol()};

flang/test/Semantics/data06.f90

@@ -28,6 +28,9 @@ subroutine s1
   integer :: a4(3)
   !ERROR: DATA statement designator 'a4(5_8)' is out of range
   data (a4(j),j=1,5,2) /3*222/
+  integer :: a5(3)
+  !ERROR: DATA statement designator 'a5(-2_8)' is out of range
+  data       a5(-2) / 1 /
   interface
     real function rfunc(x)
       real, intent(in) :: x