Cause:
This diagnostic message is emitted when the vectorizer detects that this particular computation is better performed in scalar mode.
Example:
int foo(int a, int b, int n){
int i;
for(i = 0; i < n; i++)
a = b + i;
return a;
}
$ icpc example17.c -c -vec-report2
example17.c(3): (col. 1) remark: loop was not vectorized: insufficient computational work