resolve code reviews

Author: sfzhu93

tests/mir-opt/dataflow-const-prop/array_index.rs

@@ -9,8 +9,13 @@ fn main() {
     // CHECK: let mut [[array_lit:_.*]]: [u32; 4];
     // CHECK:     debug x => [[x:_.*]];
 
-    let x: u32 = [0, 1, 2, 3][2];
     // CHECK:       [[array_lit]] = [const 0_u32, const 1_u32, const 2_u32, const 3_u32];
-    // CHECK-LABEL: assert(const true,
-    // CHECK:     [[x]] = [[array_lit]][2 of 3];
+    // CHECK-NOT:   {{_.*}} = Len(
+    // CHECK-NOT:   {{_.*}} = Lt(
+    // CHECK-NOT:   assert(move _
+    // CHECK:       {{_.*}} = const 4_usize;
+    // CHECK:       {{_.*}} = const true;
+    // CHECK-LABEL: assert(const true
+    // CHECK:       [[x]] = [[array_lit]][2 of 3];
+    let x: u32 = [0, 1, 2, 3][2];
 }