[llvm-branch-commits] [clang] release/20.x: Reduce memory usage in AST parent map generation by lazily checking if nodes have been seen (#129934) (PR #131209)

[Erich Keane via llvm-branch-commits]

erichkeane wrote:

FWIW: I'm in favor of this.  This is quite low risk/a pretty trivial change that has an incredibly big impact on the memory pressure of our compiler in certain situations.  I think this is  a good candidate to back port.

https://github.com/llvm/llvm-project/pull/131209