git: openjdk/jdk: 8252583: Clean up unused phi-to-copy degradation mechanism

[Tobias Hartmann]

Changeset: f3ea0d36
Author:    Roberto Castaneda Lozano <roberto.castaneda.lozano at oracle.com>
Committer: Tobias Hartmann <thartmann at openjdk.org>
Date:      2020-09-24 08:10:56 +0000
URL:       https://git.openjdk.java.net/jdk/commit/f3ea0d36

8252583: Clean up unused phi-to-copy degradation mechanism

Remove unused notion of 'PhiNode-to-copy degradation', where PhiNodes can be
degraded to copies by setting their RegionNode to NULL. Remove corresponding
PhiNode::is_copy() test, which always returned NULL (false). Assert that
PhiNodes have an associated RegionNode in PhiNode::Ideal().

Reviewed-by: thartmann, kvn

! src/hotspot/share/opto/addnode.cpp
! src/hotspot/share/opto/cfgnode.cpp
! src/hotspot/share/opto/cfgnode.hpp
! src/hotspot/share/opto/ifnode.cpp
! src/hotspot/share/opto/loopnode.cpp
! src/hotspot/share/opto/memnode.cpp
! src/hotspot/share/opto/subnode.cpp