RFR: 8326438: C2: assert(ld->in(1)->Opcode() == Op_LoadN) failed: Assumption invalid: input to DecodeN is not LoadN [v2]

[Daniel Lundén]

> The [`assert`](https://github.com/openjdk/jdk/blob/6f2676dc5f09d350c359f906b07f6f6d0d17f030/src/hotspot/share/opto/graphKit.cpp#L1567) added in [JDK-8310524](https://bugs.openjdk.org/browse/JDK-8310524) is too strong and may sometimes not hold due to the [GVN transformation in `LoadNode::make`](https://github.com/openjdk/jdk/blob/8cb9b479c529c058aee50f83920db650b0c18045/src/hotspot/share/opto/memnode.cpp#L973).
> 
> ### Changeset
> Remove the `assert`.
> 
> ### Testing
> N/A

Daniel Lundén has updated the pull request incrementally with one additional commit since the last revision:

  Elaborate in LoadN comment

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/18434/files
  - new: https://git.openjdk.org/jdk/pull/18434/files/c74178e7..fee1fff0

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=18434&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=18434&range=00-01

  Stats: 4 lines in 1 file changed: 3 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/18434.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/18434/head:pull/18434

PR: https://git.openjdk.org/jdk/pull/18434