Arthur Eubanks 3af427539b [Inliner] Put inline history into IR as !inline_history metadata (#190876) ...

(Reland of #190700 with checks for RefSCCs with one function with a
self-reference, plus determinism fix)

(Reland of #190092 with verifier change to look through GlobalAliases)

So that it's preserved across all inline invocations rather than just
one inliner pass run.

This prevents cases where devirtualization in the simplification
pipeline uncovers inlining opportunities that should be discarded due to
inline history, but we dropped the inline history between inliner pass
runs, causing code size to blow up, sometimes exponentially.

For compile time reasons, we want to limit this to only call sites that
have the potential to inline through SCCs, potentially with the help of
devirtualization. This means that the callee is in a non-trivial
(Ref)SCC, or the call site was previously an indirect call, which can
potentially be devirtualized to call any function.

The CGSCCUpdater::InlinedInternalEdges logic still seems to be relevant
even with this change, as monster_scc.ll blows up if I remove that code.


http://llvm-compile-time-tracker.com/compare.php?from=e830d88e8ae5f44a97cc76136a0a4e83aa9157c0&to=ed535e732fc41b79ab8efda2417886cbd0812f7f&stat=instructions:u

Fixes #186926.

2026-04-08 09:34:52 -07:00

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