added check for affine.for bounds

Author: ayokunle321

mlir/lib/Dialect/Affine/IR/AffineOps.cpp

@@ -1903,6 +1903,12 @@ LogicalResult AffineForOp::verifyRegions() {
                                              getUpperBoundMap().getNumDims())))
       return failure();
 
+  if (getLowerBoundMap().getNumResults() < 1)
+    return emitOpError("expected lower bound map to have at least one result");
+
+  if (getUpperBoundMap().getNumResults() < 1)
+    return emitOpError("expected upper bound map to have at least one result");
+    
   unsigned opNumResults = getNumResults();
   if (opNumResults == 0)
     return success();

mlir/test/Dialect/Affine/invalid.mlir

@@ -541,3 +541,25 @@ func.func @dynamic_dimension_index() {
   }) : () -> ()
   return
 }
+
+// -----
+
+#map = affine_map<() -> ()>
+#map1 = affine_map<() -> (1)>
+func.func @no_lower_bound() {
+  // expected-error@+1 {{'affine.for' op expected lower bound map to have at least one result}}
+  affine.for %i = max #map() to min #map1() {
+  }
+  return
+}
+
+// -----
+
+#map = affine_map<() -> ()>
+#map1 = affine_map<() -> (1)>
+func.func @no_upper_bound() {
+  // expected-error@+1 {{'affine.for' op expected upper bound map to have at least one result}}
+  affine.for %i = max #map1() to min #map() {
+  }
+  return
+}