[clang] [Clang] Improve concept performance 1/N (PR #188421)

[Mike Napolitano via cfe-commits]

mikeynap wrote:

> I will test this out this weekend as well -- have a project that showed a crazy regression, will post numbers before/after this patch just for the hell of it.

Results from my concept heavy codebase (hmmm looks like it wasn't a large of a regression as last time I checked, maybe the other patches you landed helped as well?). Regardless, it def helped! (fsyntax-only builds, vanilla non pgo/lto/bolt binaries)

clang-21 | clang-22 | This patch
-- | -- | --
315s | 345s | 320s




https://github.com/llvm/llvm-project/pull/188421