RFR: addressing review comments [v2]

[Vicente Romero]

> Fixing a compiler crash plus other review comments from Maurizio

Vicente Romero has updated the pull request incrementally with one additional commit since the last revision:

  additional test and bug fix

-------------

Changes:
  - all: https://git.openjdk.java.net/valhalla/pull/663/files
  - new: https://git.openjdk.java.net/valhalla/pull/663/files/11c46704..409de082

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=valhalla&pr=663&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=valhalla&pr=663&range=00-01

  Stats: 69 lines in 3 files changed: 27 ins; 3 del; 39 mod
  Patch: https://git.openjdk.java.net/valhalla/pull/663.diff
  Fetch: git fetch https://git.openjdk.java.net/valhalla pull/663/head:pull/663

PR: https://git.openjdk.java.net/valhalla/pull/663