[flang-commits] [flang] [mlir] [mlir][OpenMP] rewrite conversion of privatisation for omp.parallel (PR #111844)

[Leandro Lupori via flang-commits]

================
@@ -1421,12 +1449,56 @@ convertOmpParallel(omp::ParallelOp opInst, llvm::IRBuilderBase &builder,
             deferredStores, isByRef)))
       bodyGenStatus = failure();
 
+    // Apply copy region for firstprivate.
+    if (!privateBlockArgs.empty()) {
+      // Find the end of the allocation blocks
+      assert(afterAllocas->getSinglePredecessor());
+      builder.SetInsertPoint(
+          afterAllocas->getSinglePredecessor()->getTerminator());
+      llvm::BasicBlock *copyBlock = splitBB(builder, true, "omp.private.copy");
+      builder.SetInsertPoint(copyBlock->getFirstNonPHIOrDbgOrAlloca());
+    }
+    for (unsigned i = 0; i < privateBlockArgs.size(); ++i) {
+      if (privateDecls[i].getDataSharingType() !=
+          omp::DataSharingClauseType::FirstPrivate)
+        continue;
+
+      // copyRegion implements `lhs = rhs`
+      Region &copyRegion = privateDecls[i].getCopyRegion();
+
+      // map copyRegion rhs arg
+      llvm::Value *nonPrivateVar =
+          moduleTranslation.lookupValue(opInst.getPrivateVars()[i]);
+      assert(nonPrivateVar);
+      moduleTranslation.mapValue(copyRegion.getArgument(0), nonPrivateVar);
+
+      // map copyRegion lhs arg
+      moduleTranslation.mapValue(copyRegion.getArgument(1), llvmPrivateVars[i]);
+
+      // in-place convert copy region
+      builder.SetInsertPoint(builder.GetInsertBlock()->getTerminator());
+      if (failed(inlineConvertOmpRegions(copyRegion, "omp.private.copy",
+                                         builder, moduleTranslation))) {
+        bodyGenStatus = failure();
+        return;
+      }
+
+      // ignore unused value yielded value from copy region
----------------
luporl wrote:

```suggestion
      // ignore unused value yielded from copy region
```

https://github.com/llvm/llvm-project/pull/111844