[Openmp-commits] [clang] [openmp] [Clang][OpenMP] Fix tile/unroll on iterator- and foreach-loops. (PR #91459)

[Michael Kruse via Openmp-commits]

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@@ -182,17 +182,34 @@ class OMPLoopScope : public CodeGenFunction::RunCleanupsScope {
             }
             return false;
           });
-      PreInits = cast_or_null<DeclStmt>(LD->getPreInits());
+      PreInits = LD->getPreInits();
     } else if (const auto *Tile = dyn_cast<OMPTileDirective>(&S)) {
-      PreInits = cast_or_null<DeclStmt>(Tile->getPreInits());
+      PreInits = Tile->getPreInits();
     } else if (const auto *Unroll = dyn_cast<OMPUnrollDirective>(&S)) {
-      PreInits = cast_or_null<DeclStmt>(Unroll->getPreInits());
+      PreInits = Unroll->getPreInits();
     } else {
       llvm_unreachable("Unknown loop-based directive kind.");
     }
     if (PreInits) {
-      for (const auto *I : PreInits->decls())
-        CGF.EmitVarDecl(cast<VarDecl>(*I));
+      // CompoundStmts and DeclStmts are used as lists of PreInit statements and
+      // declarations. Since declarations must be visible in the the following
+      // that they initialize, unpack the ComboundStmt they are nested in.
+      SmallVector<const Stmt *> PreInitStmts;
+      if (auto *PreInitCompound = dyn_cast<CompoundStmt>(PreInits))
+        llvm::append_range(PreInitStmts, PreInitCompound->body());
+      else
+        PreInitStmts.push_back(PreInits);
+
+      for (const Stmt *S : PreInitStmts) {
+        // EmitStmt skips any OMPCapturedExprDecls, but needs to be emitted
+        // here.
+        if (auto *PreInitDecl = dyn_cast<DeclStmt>(S)) {
----------------
Meinersbur wrote:

Everything else is emitted in `CGF.EmitStmt(S);` at line 211.

`CGF.EmitStmt(S)` does itself call `CGF.EmitVarDecl(S)` if passed a DeclStmts, so this special handling should not be necessary. It includes, however, an exception for `OMPCapturedExprDecl` (subclass of `VarDecl`) that are NOT emitted so we need to do this explicitly here. Otherwise, lines 203-212 would be just a single `CGF.EmitStmt(S)`.

https://github.com/llvm/llvm-project/blob/a15b685c2d868eaf408d05baa50baa3c9f5cc740/clang/lib/CodeGen/CGDecl.cpp#L129

https://github.com/llvm/llvm-project/pull/91459