message: Use regex instead of hardcoded SSA value numbers.
  The actual numbers aren't important now, will be once we start checking values.
diff: @@ -10,20 +10,20 @@ func @fn() {
  }
  // CHECK: block {
  -// CHECK: for(idx($12)=$16 to $4 step $17) {
  -// CHECK: for(idx($13)=$16 to $5 step $17) {
  -// CHECK: for(idx($14)=$16 to $6 step $17) {
  -// CHECK: for(idx($15)=$16 to $7 step $17) {
  -// CHECK: lhs($18) = store( ... );
  +// CHECK: for(idx({{.*}})=[[zero1:.*]] to {{.*}} step [[step1:.*]]) {
  +// CHECK: for(idx({{.*}})=[[zero1]] to {{.*}} step [[step1]]) {
  +// CHECK: for(idx({{.*}})=[[zero1]] to {{.*}} step [[step1]]) {
  +// CHECK: for(idx({{.*}})=[[zero1]] to {{.*}} step [[step1]]) {
  +// CHECK: lhs({{.*}}) = store( ... );
  // CHECK: };
  // CHECK: };
  // CHECK: };
  // CHECK: }
  // CHECK: }
  // CHECK: block {
  -// CHECK: for(idx($27)=$29 to $23 step $30) {
  -// CHECK: for(idx($28)=$29 to $24 step $30) {
  -// CHECK: lhs($31) = store( ... );
  +// CHECK: for(idx({{.*}})=[[zero2:.*]] to {{.*}} step [[step2:.*]]) {
  +// CHECK: for(idx({{.*}})=[[zero2]] to {{.*}} step [[step2]]) {
  +// CHECK: lhs({{.*}}) = store( ... );
  // CHECK: };
  // CHECK: }
  // CHECK: }
  