[lworld] RFR: 8371357: [lworld] Remove EnableValhalla

[Stefan Karlsson]

On Tue, 25 Nov 2025 13:37:46 GMT, Paul Hübner <phubner at openjdk.org> wrote:

> Hi all,
> 
> This removes the `EnableValhalla` in favour of the `--enable-preview` flag. Concretely:
> * I've replaced most of the `EnableValhalla` checks with `Arguments::is_valhalla_enabled()`. 
> * Some checks were redundant and could be removed entirely.
> * I've made the `EnableValhalla` flag obsolete.
> * Some tests had to be updated.
> 
> This greatly changes the semantics of tests. I've refined some test groups to make it easier.
> 
> Testing: tiers 1-4.

Looks good minus one nit.

src/hotspot/share/opto/callnode.cpp line 1948:

> 1946:     Node* proto_adr = phase->transform(new AddPNode(klass_node, klass_node, phase->MakeConX(in_bytes(Klass::prototype_header_offset()))));
> 1947:     mark_node = LoadNode::make(*phase, control, mem, proto_adr, TypeRawPtr::BOTTOM, TypeX_X, TypeX_X->basic_type(), MemNode::unordered);
> 1948:     // EnavleValhalla legacy

Suggestion:

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Marked as reviewed by stefank (Author).

PR Review: https://git.openjdk.org/valhalla/pull/1759#pullrequestreview-3578598315
PR Review Comment: https://git.openjdk.org/valhalla/pull/1759#discussion_r2619743262