[clang] Improve stack usage to increase recursive initialization depth (PR #88546)

[Nikita Popov via cfe-commits]

nikic wrote:

This change seems to cause significant compile-time regressions for C++ code (https://llvm-compile-time-tracker.com/compare.php?from=184ba038ac1d444980b3e554b0057f3f30c516ab&to=4082a7554521572a65a5a0008c4661a534df659d&stat=instructions%3Au).

Probably most damning are the times for the clang build itself (https://llvm-compile-time-tracker.com/compare_clang.php?from=184ba038ac1d444980b3e554b0057f3f30c516ab&to=4082a7554521572a65a5a0008c4661a534df659d&stat=instructions%3Au&sortBy=interestingness) where files like X86ISelDAGToDAG.cpp regress by >3% even in an optimized build.

https://github.com/llvm/llvm-project/pull/88546