RFR: 8277239: SIGSEGV in vrshift_reg_maskedNode::emit [v2]

[Jatin Bhateja]

> Currently instruction selector differentiates between the two kinds of vector shift operations i.e. one with vector shift count and other with scalar shift count passed though LShiftCntV/RShiftCntV nodes by looking at the ideal opcode of shift count node.
> 
> A more robust scheme is to set a flag over vector shift node if it has variable vector shift count and replace the opcode based check with flag based check in various shift instruction selection patterns.

Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:

  8277239: Review comments resolution.

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/6431/files
  - new: https://git.openjdk.java.net/jdk/pull/6431/files/97dce5ca..41d33df0

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=6431&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=6431&range=00-01

  Stats: 2 lines in 1 file changed: 0 ins; 1 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6431.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6431/head:pull/6431

PR: https://git.openjdk.java.net/jdk/pull/6431