The following testcase asserts on ionmonkey revision 407632130d1b (run with --ion -n -m): gc(); evaluate("gcslice(0);");
jsfunfuzz hits this a lot, too. autoBisect shows this is probably related to the following changeset: The first bad revision is: changeset: 96013:d5545e6d927b user: David Anderson date: Tue May 22 23:17:57 2012 -0700 summary: Throw Ion code away when needsBarrier changes (bug 757412, r=sstangl).
JSBugMon: The testcase found in this bug no longer reproduces (tried revision 80a444262772).
Confirming that this no longer occurs, the following changeset might have fixed it: autoBisect shows this is probably related to the following changeset: The first good revision is: changeset: 96132:80a444262772 user: David Anderson date: Tue May 29 21:03:22 2012 -0400 summary: Merge backout.
Automatically extracted testcase for this bug was committed: https://hg.mozilla.org/mozilla-central/rev/2e891e0db397