Is it possible to use `__sec_implicit_index` inside an `if` block statement using Cilk Plus Array Notation?

Question

My goal is to conditionally assign values to an array based on the implicit index value, using Cilk Plus Array Notation with Intel's icc compiler, version 13.1.3 20130607.

Consider the following code:

    T test[10] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
    if(test[:] < 5) {
        test[:] = 10 - __sec_implicit_index(0);
    }

This code compiles fine, but when I try to run it, I get the following error:

undefined symbol: __sec_implicit_index

Note Although this might look like a linking error, it is not, since the following code compiles and runs fine (the condition has been removed):

T test[10] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
test[:] = 10 - __sec_implicit_index(0);

So, my question: is it possible to accomplish the behaviour of the conditional code below using Cilk Plus Array Notation?

    T test[10] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
    for(int i = 0; i < 10; i++) {
        if(i < 5) {
            test[i] = 10 - i;
        }
    }

Answer 1

The example is correct. The problem is a bug in icc 13.1.3. icc 14.0 beta correctly compiled and executed the example for me.

For icc 13.1.3, I have found #pragma simd to be more reliable, in general, as a way to indicate permission to vectorize. With it, your example looks like:

T test[10] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
#pragma simd
for(int i = 0; i < 10; i++) {
    if(i < 5) {
        test[i] = 10 - i;
    }
}

It of course loses the notational convenience of array notation.