[jdk17] RFR: 8269088: C2 fails with assert(!n->is_Store() && !n->is_LoadStore()) failed: no node with a side effect [v2]

[Roland Westrelin]

> In PhaseIdealLoop::try_sink_out_of_loop(), a Store is not expected to
> be a candidate for sinking: if a Store is in a loop, there has to be
> at least a memory Phi keeping the Store in the loop. In the case of
> the failure, a Store has control set in a loop but the Store is not
> connected to a loop memory Phi. The reason for that is that the Store
> was moved out of loop by PhaseIdealLoop::try_move_store_after_loop()
> which moved the Store to the lca of its uses (other than the loop
> Phi), in this case another loop.
> 
> It doesn't look right that a Store is removed from a loop only to be
> added to another one so I propose fixing that by placing the Store
> right out of the loop it's being moved out of (similar to
> PhaseIdealLoop::try_sink_out_of_loop()) rather than at the lca of
> uses.

Roland Westrelin has updated the pull request incrementally with one additional commit since the last revision:

  comment

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

Changes:
  - all: https://git.openjdk.java.net/jdk17/pull/133/files
  - new: https://git.openjdk.java.net/jdk17/pull/133/files/dcb1e646..67e35b0e

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk17&pr=133&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk17&pr=133&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.java.net/jdk17/pull/133.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk17 pull/133/head:pull/133

PR: https://git.openjdk.java.net/jdk17/pull/133