[jdk17u-dev] RFR: 8307683: Loop Predication should not hoist range checks with trap on success projection by negating their condition

[Goetz Lindenmaier]

This fixes a regression in 17.0.7.  To work around the regression, JDK-8297951 was backed out in 17.0.8.

Big parts of this change is passing a Proj node instead of the If that is the predecessor of the Proj through method calls. As methods differ in their arguments in 17, all these had to be resolved.
The real fix is in loop_predication_impl_helper().

Resolves in detail:

src/hotspot/share/opto/loopPredicate.cpp
In head, there are two variants of is_range_check_if(), 17 has only one. Omitted the changes to the second one.
loop_predication_impl_helper()
Renamed the variable. In head, it is if_proj->if_success_proj, here it is proj->success_proj.
I introduce a new vairalbe IfProjNode if_success_proj. Calls to loop_predication_impl_helper
pass Projs and not IfProjs, so this seems cleaner.  Added assertion.
Passing proj instead of if to is_range_check_if().
Computation of the deleted "bool negate" differs.  Deleted anyways.
Removed all the uses of negate.

src/hotspot/share/opto/loopTransform.cpp
Trivial resolve.

src/hotspot/share/opto/loopnode.cpp
extract_long_range_checks() was introduced in "8259609: C2: optimize long range checks in long counted loops".
The change is only needed as the input to is_range_check_if() was
changed from the IfNode to the IfProjNode below. The change here has no effect on the fix. Skipped.

patching file src/hotspot/share/opto/loopnode.hpp
Resolved, simple differences.

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Commit messages:
 - Backport dfd3da3f52480f68f653beb1e720691f8232ace7

Changes: https://git.openjdk.org/jdk17u-dev/pull/1553/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk17u-dev&pr=1553&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8307683
  Stats: 256 lines in 4 files changed: 227 ins; 6 del; 23 mod
  Patch: https://git.openjdk.org/jdk17u-dev/pull/1553.diff
  Fetch: git fetch https://git.openjdk.org/jdk17u-dev.git pull/1553/head:pull/1553

PR: https://git.openjdk.org/jdk17u-dev/pull/1553