RFR: 8237949: CTW: C1 compilation fails with "too many stack slots used"

[Jamsheed C M]

Hi all,

As part of the enhancement requirement from truffle use case [1] 
OopMapValue was extended by 2 bits,  this change will be automatically 
handled in c1 here [2].

There was a day one code[3] that handled this case before [2] covering 
more cases than Oop cases. But it seems this extension is not really 
useful for C1 java use case.

So the earlier bailout is preserved with change in the comments. [4]

Request for review

JBS: https://bugs.openjdk.java.net/browse/JDK-8237949

webrev: http://cr.openjdk.java.net/~jcm/8237949/webrev.00/

Best regards,

Jamsheed

[1] https://bugs.openjdk.java.net/browse/JDK-8231586

[2] 
https://github.com/openjdk/jdk/blob/master/src/hotspot/share/c1/c1_LinearScan.hpp#L341

[3] 
https://github.com/openjdk/jdk/blob/master/src/hotspot/share/c1/c1_LinearScan.cpp#L246

[4] 
http://cr.openjdk.java.net/~jcm/8237949/webrev.00/src/hotspot/share/c1/c1_LinearScan.cpp.udiff.html