[flang-commits] [flang] [ACC] Add support for force clause for loop collapse (PR #162534)

[Razvan Lupusoru via flang-commits]

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@@ -3190,22 +3190,47 @@ class FirConverter : public Fortran::lower::AbstractConverter {
         std::get_if<Fortran::parser::OpenACCCombinedConstruct>(&acc.u);
 
     Fortran::lower::pft::Evaluation *curEval = &getEval();
+    // Determine collapse depth/force and loopCount
+    bool collapseForce = false;
+    uint64_t collapseDepth = 1;
+    uint64_t loopCount = 1;
+    auto parseCollapse = [&](const Fortran::parser::AccClauseList &cl)
+                             -> std::pair<bool, uint64_t> {
+      bool force = false;
+      uint64_t depth = 1;
+      for (const Fortran::parser::AccClause &clause : cl.v) {
+        if (const auto *collapseClause =
+                std::get_if<Fortran::parser::AccClause::Collapse>(&clause.u)) {
+          const Fortran::parser::AccCollapseArg &arg = collapseClause->v;
+          force = std::get<bool>(arg.t);
+          const auto &intExpr =
+              std::get<Fortran::parser::ScalarIntConstantExpr>(arg.t);
+          if (const auto *expr = Fortran::semantics::GetExpr(intExpr)) {
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razvanlupusoru wrote:

Having collapse clause parsing in a single place would be ideal. We currently have `getLoopCountForCollapseAndTile` in OpenACC.cpp. Any chance to make something similar - like getLoopCountForCollapse - and then use it both here and in getLoopCountForCollapseAndTile.

https://github.com/llvm/llvm-project/pull/162534