[clang] [Analyzer][CFG] Correctly handle rebuilt default arg and default init expression (PR #91879)

[Alan Zhao via cfe-commits]

alanzhao1 wrote:

FYI this patch messes up some diagnostics with `-Wunreachable-code`: https://godbolt.org/z/6TEdrx55d

If the unreachable code is a constructor with a default parameter that is a builtin function, clang incorrectly highlights the call to the builtin instead of the call to the constructor.

There's a similar issue if instead of a builtin the default parameter is the return value of another function which itself has default parameter that is a builtin: https://godbolt.org/z/ErarnbGbY

This was originally observed in Chrome - see https://crbug.com/343231820.



https://github.com/llvm/llvm-project/pull/91879