review for 6707044 (XS): uncommon_trap of ifnull bytecode leaves garbage on expression stack

[Chuck Rasbold]

http://webrev.invokedynamic.info/rasbold/6707044

6707044: uncommon_trap of ifnull bytecode leaves garbage on expression stack
Summary: Remove call to repush_if_args()
Reviewed-by:

When an ifnull or ifnonnull bytecode that has never been reached is
compiled by the JIT, it is turned into an uncommon_trap.  The path
along that uncommon_trap mistakenly leaves an extra, dirty, element on
the top of JVM expression stack, causing havoc down the line.

The fix is to remove the call to repush_if_args(), since the bytecode
operand was never popped from the stack in the first place.