RFR: 8343148: C2: Refactor uses of "PhaseValue::*con*() + PhaseIdealLoop::set_ctrl()" into separate method [v6]

[theoweidmannoracle]

> This patch introduces the methods `PhaseIdealLoop::intcon` and `PhaseIdealLoop::longcon` which are wrappers for:
> 
> 
> ConINode* node = _igvn.intcon(i);
> set_ctrl(node, C->root());
> 
> 
> and
> 
> 
> ConLNode* node = _igvn.longcon(i);
> set_ctrl(node, C->root());
> 
> 
> Occurrences of this pattern in loopnode.cpp were replaced with the appropriate call to the new methods.

theoweidmannoracle has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains nine commits:

 - Merge branch 'master' into JDK-8343148
 - Improve brace style
 - Add set_root_as_ctrl
 - Update src/hotspot/share/opto/loopopts.cpp
   
   Co-authored-by: Emanuel Peter <emanuel.peter at oracle.com>
 - Update src/hotspot/share/opto/loopopts.cpp
   
   Co-authored-by: Emanuel Peter <emanuel.peter at oracle.com>
 - Update src/hotspot/share/opto/loopopts.cpp
   
   Co-authored-by: Emanuel Peter <emanuel.peter at oracle.com>
 - Update src/hotspot/share/opto/loopTransform.cpp
   
   Co-authored-by: Emanuel Peter <emanuel.peter at oracle.com>
 - Add helper methods for zerocon, makecon, and integercon too
 - 8343148: C2: Refactor uses of "PhaseValues::intcon() + PhaseIdealLoop::set_ctrl()" into separate method

-------------

Changes: https://git.openjdk.org/jdk/pull/21836/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21836&range=05
  Stats: 130 lines in 7 files changed: 44 ins; 42 del; 44 mod
  Patch: https://git.openjdk.org/jdk/pull/21836.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21836/head:pull/21836

PR: https://git.openjdk.org/jdk/pull/21836