This is failing jit-tests/tests/ion/bug670484.js on IM TBPL, x64 only, with --ion --ion-eager --ion-gvn=off. It might be a register allocation bug:
9 callgeneric ([x:9 (=rcx)]) (=rdx) t=([p:7 (=rbp)], [p:8 (=rbx)]) <|@
0 movegroup ()[=rax -> =rcx] <|@
10 return () (=rcx) <|@
This movegroup looks bad - it clobbers the outgoing return register with something bogus.
*** Bug 701554 has been marked as a duplicate of this bug. ***
Created attachment 573707 [details] [diff] [review]
My fault. I botched JSClobberMask last week.
Created attachment 573877 [details] [diff] [review]
Fix typo in previous fix typo.