Fix Trac #9013
- ran validate
- ran T9013 test with all ways
- ran CarryOverflow test with all ways, for good measure
I am eager to fix Trac #9013 not just for its own sake but also because I intend to implement x86-specific code generation for addIntC# and subIntC# using the overflow flag. (In my small Integer addition microbenchmark I get around a 6% speedup.) That code will be similar to the code for plusWord2# and subject to the same issue.
Also, there is quite a lot of code duplication between genCCall32 and genCCall64. I would be happy to look into factoring out the common parts in a separate commit.