FULL PRODUCT VERSION :
jdk8 u66, jdk9 u108

FULL OS VERSION :
openSuse 42.1 - 64bit
kernel 4.1.15-8-default

A DESCRIPTION OF THE PROBLEM :
I wanted to try, if hotspot can optimize pair of divide / modulo with same arguments to one instruction.
I made little program, and found strange behaviour. If it counts div only (comment mod line), it runs with constant speed.

0 3741 1197102800
1 3506 1197102800
2 3512 1197102800
3 3503 1197102800
4 3498 1197102800
.....

If it counts div/mod pair, it starts as fast as previous case, but it slows down after few iterations.

0 3687 -1176719460
1 3509 -1176719460
2 7020 -1176719460
3 7022 -1176719460
4 7021 -1176719460
...

Sometimes speed changes more times, it prints something like

0 fast
1 fast
2 slow
3 fast
4 fast
5 slow
.. slow

THE PROBLEM WAS REPRODUCIBLE WITH -server FLAG: Yes

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
run given microbenchmark (i know, it is not best microbenchmark:)


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
public final class Test {
public static void main(final String[] args) {
new Test().test();
}

private void test() {
for (int i = 0; i < 100000; i++) {
long ts = System.nanoTime();
int sum = aaa();
System.out.println(i + "\t" + ((System.nanoTime() - ts) / 1000000) + "\t" + sum);
}
}

private int aaa() {
int sum = 0;
for (int i = 1; i < 100000; i++){
for (int j = 1; j < 10000; j++){
int d = i / j;
int m = i % j;
sum += d;
sum += m;
}
}
return sum;
}
}
---------- END SOURCE ----------