[Mlir-commits] [mlir] [WIP][flang][OpenMP] Translate OpenMP scopes when compiling for target device (PR #130078)

[Sergio Afonso]

================
@@ -5255,6 +5256,49 @@ convertTargetOpsInNest(Operation *op, llvm::IRBuilderBase &builder,
               return WalkResult::interrupt();
             return WalkResult::skip();
           }
+
+          // Non-target ops might nest target-related ops, therefore, we
+          // translate them as non-OpenMP scopes. Translating them is needed by
+          // nested target-related ops since they might LLVM values defined in
+          // their parent non-target ops.
+          if (isa<omp::OpenMPDialect>(oper->getDialect()) &&
+              oper->getParentOfType<LLVM::LLVMFuncOp>() &&
+              !oper->getRegions().empty()) {
+
+            // TODO Handle other ops with entry block args.
+            if (auto wsloop = dyn_cast<omp::WsloopOp>(oper)) {
+              auto blockArgIface = cast<omp::BlockArgOpenMPOpInterface>(oper);
+              if (blockArgIface) {
+                forwardArgs(moduleTranslation,
+                            blockArgIface.getPrivateBlockArgs(),
+                            wsloop.getPrivateVars());
+                forwardArgs(moduleTranslation,
+                            blockArgIface.getReductionBlockArgs(),
+                            wsloop.getReductionVars());
+              }
+            }
+
+            if (auto loopNest = dyn_cast<omp::LoopNestOp>(oper)) {
+              for (auto iv : loopNest.getIVs()) {
+                // Create fake allocas just to maintain IR validity.
+                moduleTranslation.mapValue(
+                    iv, builder.CreateAlloca(
+                            moduleTranslation.convertType(iv.getType())));
+              }
+            }
+
+            for (Region &region : oper->getRegions()) {
+              auto result = convertOmpOpRegions(
+                  region, oper->getName().getStringRef().str() + ".fake.region",
+                  builder, moduleTranslation);
+              if (result.takeError())
+                return WalkResult::interrupt();
----------------
skatrak wrote:

```suggestion
              if (failed(handleError(result, oper)))
                return failure();
```

https://github.com/llvm/llvm-project/pull/130078