[flang] [llvm] [FLANG][OpenMP]Add frontend support for ASSUME and ASSUMES (PR #120770)

[Krzysztof Parzyszek via llvm-commits]

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@@ -4174,6 +4215,49 @@ struct OmpClauseList {
 
 // --- Directives and constructs
 
+// Ref: [5.2: 213-216]
+//
+// assume-construct ->
+//   ASSUME absent-clause | contains-clause | holds-clause | no-openmp-clause |
+//          no-openmp-routines-clause | no-parallelism-clause
+struct OpenMPAssumeConstruct {
+  TUPLE_CLASS_BOILERPLATE(OpenMPAssumeConstruct);
+  std::tuple<Verbatim, OmpClauseList> t;
+  CharBlock source;
+};
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kparzysz wrote:

The `OpenMPDeclarativeAssumes` below is what we need (based on the name, that is).  The `ASSUMES` (with `S` at the end) is the declarative thing, which applies to the entire compilation unit.  There is no `END ASSUMES`.

https://github.com/llvm/llvm-project/pull/120770