7128355: assert(!nocreate) failed: Cannot build a phi for a block already parsed
Summary: Do not common BoxLock nodes and avoid creating phis of boxes.
Reviewed-by: never
6888336: G1: avoid explicitly marking and pushing objects in survivor spaces
Summary: This change simplifies the interaction between GC and concurrent marking. By disabling survivor spaces during the initial-mark pause we don't need to propagate marks of objects we copy during each GC (since we never need to copy an explicitly marked object).
Reviewed-by: johnc, brutisso