Different warning

Author: ivanradanov

flang/lib/Optimizer/OpenMP/LowerWorkshare.cpp

@@ -94,11 +94,9 @@ bool shouldUseWorkshareLowering(Operation *op) {
   if (isNestedIn<omp::SingleOp>(parentWorkshare, op))
     return false;
 
-  if (parentWorkshare.getRegion().getBlocks().size() != 1) {
-    parentWorkshare->emitWarning(
-        "omp workshare with unstructured control flow currently unsupported.");
+  // Do not use workshare lowering until we support CFG in omp.workshare
+  if (parentWorkshare.getRegion().getBlocks().size() != 1)
     return false;
-  }
 
   return true;
 }
@@ -448,6 +446,9 @@ LogicalResult lowerWorkshare(mlir::omp::WorkshareOp wsOp, DominanceInfo &di) {
   } else {
     // Otherwise just change the operation to an omp.single.
 
+    wsOp->emitWarning("omp workshare with unstructured control flow currently "
+                      "unsupported and will be serialized.");
+
     // `shouldUseWorkshareLowering` should have guaranteed that there are no
     // omp.workshare_loop_wrapper's that bind to this omp.workshare.
     assert(!wsOp->walk([&](Operation *op) {

flang/test/Transforms/OpenMP/lower-workshare-todo-cfg-dom.mlir

@@ -1,5 +1,7 @@
 // RUN: fir-opt --lower-workshare --allow-unregistered-dialect %s 2>&1 | FileCheck %s
 
+// CHECK: warning: omp workshare with unstructured control flow currently unsupported and will be serialized.
+
 // CHECK: omp.parallel
 // CHECK-NEXT: omp.single
 

flang/test/Transforms/OpenMP/lower-workshare-todo-cfg.mlir

@@ -1,5 +1,7 @@
 // RUN: fir-opt --lower-workshare --allow-unregistered-dialect %s 2>&1 | FileCheck %s
 
+// CHECK: warning: omp workshare with unstructured control flow currently unsupported and will be serialized.
+
 // CHECK: omp.parallel
 // CHECK-NEXT: omp.single