[flang] Relax ETIME(VALUES=) runtime checking (#107647)

Don't require the "VALUES=" argument to the extension intrinsic
procedure ETIME to have exactly two elements. Other compilers that
support ETIME do not, and it's easy to adapt the behavior to whatever
the dynamic size turns out to be.

Author: klausler

flang/runtime/time-intrinsic.cpp

@@ -490,16 +490,20 @@ void RTNAME(Etime)(const Descriptor *values, const Descriptor *time,
     auto typeCode{values->type().GetCategoryAndKind()};
     // ETIME values argument must have decimal range == 2.
     RUNTIME_CHECK(terminator,
-        values->rank() == 1 && values->GetDimension(0).Extent() == 2 &&
-            typeCode && typeCode->first == Fortran::common::TypeCategory::Real);
+        values->rank() == 1 && typeCode &&
+            typeCode->first == Fortran::common::TypeCategory::Real);
     // Only accept KIND=4 here.
     int kind{typeCode->second};
     RUNTIME_CHECK(terminator, kind == 4);
-
-    ApplyFloatingPointKind<StoreFloatingPointAt, void>(
-        kind, terminator, *values, /* atIndex = */ 0, usrTime);
-    ApplyFloatingPointKind<StoreFloatingPointAt, void>(
-        kind, terminator, *values, /* atIndex = */ 1, sysTime);
+    auto extent{values->GetDimension(0).Extent()};
+    if (extent >= 1) {
+      ApplyFloatingPointKind<StoreFloatingPointAt, void>(
+          kind, terminator, *values, /* atIndex = */ 0, usrTime);
+    }
+    if (extent >= 2) {
+      ApplyFloatingPointKind<StoreFloatingPointAt, void>(
+          kind, terminator, *values, /* atIndex = */ 1, sysTime);
+    }
   }
 
   if (time) {