[flang-commits] [flang] [Flang][OpenMP] Add Semantics support for Nested OpenMPLoopConstructs (PR #145917)

[Krzysztof Parzyszek via flang-commits]

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@@ -135,31 +142,74 @@ class CanonicalizationOfOmp {
       if (auto *doCons{GetConstructIf<parser::DoConstruct>(*nextIt)}) {
         if (doCons->GetLoopControl()) {
           // move DoConstruct
-          std::get<std::optional<parser::DoConstruct>>(x.t) =
+          std::get<std::optional<std::variant<parser::DoConstruct,
+              common::Indirection<parser::OpenMPLoopConstruct>>>>(x.t) =
               std::move(*doCons);
           nextIt = block.erase(nextIt);
           // try to match OmpEndLoopDirective
-          if (nextIt != block.end()) {
+          if (auto *endDir{
+                  GetConstructIf<parser::OmpEndLoopDirective>(*nextIt)}) {
+            std::get<std::optional<parser::OmpEndLoopDirective>>(x.t) =
+                std::move(*endDir);
+            nextIt = block.erase(nextIt);
+          }
+        } else {
+          messages_.Say(dir.source,
+              "DO loop after the %s directive must have loop control"_err_en_US,
+              parser::ToUpperCaseLetters(dir.source.ToString()));
+        }
+      } else if (auto *ompLoopCons{
+                     GetOmpIf<parser::OpenMPLoopConstruct>(*nextIt)}) {
+        // We should allow UNROLL and TILE constructs to be inserted between an
+        // OpenMP Loop Construct and the DO loop itself
+        auto &beginDirective =
+            std::get<parser::OmpBeginLoopDirective>(ompLoopCons->t);
+        auto &beginLoopDirective =
+            std::get<parser::OmpLoopDirective>(beginDirective.t);
+        if ((beginLoopDirective.v == llvm::omp::Directive::OMPD_unroll ||
+                beginLoopDirective.v == llvm::omp::Directive::OMPD_tile)) {
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kparzysz wrote:

Too many parentheses.

https://github.com/llvm/llvm-project/pull/145917