[flang-commits] [flang] [flang][OpenMP][Lower] lower array subscripts for task depend (PR #132994)

[Tom Eccles via flang-commits]

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@@ -830,18 +845,38 @@ bool ClauseProcessor::processDepend(mlir::omp::DependClauseOps &result) const {
 
     for (const omp::Object &object : objects) {
       assert(object.ref() && "Expecting designator");
+      mlir::Value dependVar;
 
       if (evaluate::ExtractSubstring(*object.ref())) {
         TODO(converter.getCurrentLocation(),
              "substring not supported for task depend");
       } else if (evaluate::IsArrayElement(*object.ref())) {
-        TODO(converter.getCurrentLocation(),
-             "array sections not supported for task depend");
+        // Array Section
+        SomeExpr expr = *object.ref();
+        if (isVectorSubscript(expr))
+          TODO(converter.getCurrentLocation(),
+               "Vector subscripted array section for task dependency");
+
+        hlfir::EntityWithAttributes entity = convertExprToHLFIR(
+            converter.getCurrentLocation(), converter, expr, symMap, stmtCtx);
+        dependVar = entity.getBase();
+      } else {
+        semantics::Symbol *sym = object.sym();
+        dependVar = converter.getSymbolAddress(*sym);
       }
 
-      semantics::Symbol *sym = object.sym();
-      const mlir::Value variable = converter.getSymbolAddress(*sym);
-      result.dependVars.push_back(variable);
+      // The openmp dialect doesn't know what to do with boxes (and it would
+      // break layering to teach it about them). The dependency variable can be
+      // a box because it was an array section or because the original symbol
+      // was mapped to a box.
+      // Getting the address of the box data is okay because all the runtime
+      // ultimately cares about is the base address of the array.
+      if (fir::isa_box_type(dependVar.getType())) {
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tblah wrote:

The standard says that using an unallocated allocatable is undefined behavior. So I don't think this needs any special handling here.

https://github.com/llvm/llvm-project/pull/132994