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vectorization cost macro TARGET_VECTORIZE_ADD_STMT_COST


All:

The definition of the following macro that determine the statement cost that adds to vectorization cost.

#define TARGET_VECTORIZE_ADD_STMT_COST.

In the implementation of the above macro the following is done for many vectorization supported architectures like i386, ARM.

if (where == vect_body && stmt_info && stmt_in_inner_loop_p (stmt_info))
        count *= 50;  /* FIXME.  */

I have the  following questions.

1. Why the multiplication factor of 50 is choosen?
2. The comment mentions that the inner loop relative to the loop being vectorized is added more weight. If more weight is added to
the inner loop for the loop being vectorized, the chances of vectorizing the inner loop decreases. Why the inner loop cost is increased
with relative to the loop being vectorized?

Thanks & Regards
Ajit


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