The most straightforward extension to D150851 would involve a loop with
decreasing induction variable, with a constant start value.
iv-select-cmp.ll only contains a negative test for the decreasing
induction variable case when the start value is variable, namely
not_vectorized_select_decreasing_induction_icmp. Hence, add a test for
the most straightforward extension to D150851, in preparation to
vectorize:
long rdx = 331;
for (long i = 19999; i >= 0; i--) {
if (a[i] > 3)
rdx = i;
}
return rdx;
Differential Revision: https://reviews.llvm.org/D156152
