[MLIR][Affine] Add check for 'affine.for' Bound Map Results (llvm#127105

)

Fixes issue llvm#120001.

Add missing check in affine.for op's verifier for lower/upper bound maps
to have at least one result.

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

@@ -1902,6 +1902,10 @@ LogicalResult AffineForOp::verifyRegions() {
     if (failed(verifyDimAndSymbolIdentifiers(*this, getUpperBoundOperands(),
                                              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)

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
+}