RFR: 8330247: C2: CTW fail with assert(adr_t->is_known_instance_field()) failed: instance required

[Vladimir Kozlov]

On Fri, 19 Apr 2024 00:35:16 GMT, Cesar Soares Lucas <cslucas at openjdk.org> wrote:

> The logic in reduce allocation merges (RAM) makes use of `PhaseMacroExpand:;can_eliminate_allocation` to check whether an allocation can be scalar replaced. However, we can only SR allocations of exact types - due to rematerialization logic.
> 
> The scalar replacement logic not related to RAM has this check in `split_unique_types` so there is no performance regression by adding this check here.
> 
> Tested on Linux x64 tiers1-3.

Good.

Did you run CTW test from bug report? Is it possible to extract simple reproducer from it and add it to this PR?

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PR Review: https://git.openjdk.org/jdk/pull/18851#pullrequestreview-2010308253