[mlir][transform] Guard parametric loop tiling pass from no option

mlir/test/Transforms/invalid-outer-loop-size.mlir

@@ -0,0 +1,15 @@
+// RUN: mlir-opt -test-extract-fixed-outer-loops %s -verify-diagnostics
+
+// CHECK-LABEL: @no_crash
+func.func @no_crash(%arg0: memref<?x?xf32>) {
+  // expected-error@-5 {{expect non-empty outer loop sizes}}
+  %c2 = arith.constant 2 : index
+  %c44 = arith.constant 44 : index
+  %c1 = arith.constant 1 : index
+  scf.for %i = %c2 to %c44 step %c1 {
+    scf.for %j = %c1 to %c44 step %c2 {
+      memref.load %arg0[%i, %j]: memref<?x?xf32>
+    }
+  }
+  return
+}

mlir/test/lib/Dialect/SCF/TestLoopParametricTiling.cpp

@@ -40,6 +40,11 @@ class SimpleParametricLoopTilingPass
   }
 
   void runOnOperation() override {
+    if (sizes.empty()) {
+      getOperation()->emitError("expect non-empty outer loop sizes");
+      signalPassFailure();
+      return;
+    }
     getOperation()->walk([this](scf::ForOp op) {
       // Ignore nested loops.
       if (op->getParentRegion()->getParentOfType<scf::ForOp>())