[15] RFR: 8237894: CTW: C1 compilation fails with assert(x->type()->tag() == f->type()->tag()) failed: should have same type

[Jamsheed C M]

Hi,

Request for review the code change made for disabling value numbering 
for always null access instruction in c1 code. value numbering these 
instructions was causing asserts while processing dead code paths in 
debug builds.

webrev: http://cr.openjdk.java.net/~jcm/8237894/webrev/

bug: https://bugs.openjdk.java.net/browse/JDK-8237894

Best regards,

Jamsheed