RFR(M): 8244504: C2: refactor counted loop code in preparation for long counted loop

[John Rose]

On May 6, 2020, at 2:33 AM, Roland Westrelin <rwestrel at redhat.com> wrote:
> 
> 
> https://bugs.openjdk.java.net/browse/JDK-8244504
> http://cr.openjdk.java.net/~roland/8244504/webrev.00/
> 
> This is some refactoring in the counted loop code to prepare for 8223051
> (support loops with long (64b) trip counts). Some of the changes came up
> in the review of 8223051 (that patch used to be part of 8223051).

Very quick comment: this looks wrong:

+  jlong hi = uhi > (julong)max_jint && ulo < (julong)max_jint ? max_jint : MAX2((jlong)uhi, (jlong)ulo);

max_jint should be max_jlong, no?  I suppose it’s from an incompletely
edited copy/paste.