api: add replace_by_if helper to control ssa value replacement

[superlopuh]

Resolves #3190

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.01%. Comparing base (25506b3) to head (b537370).
Report is 24 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3196      +/-   ##
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- Coverage   90.01%   90.01%   -0.01%     
==========================================
  Files         431      431              
  Lines       54282    54294      +12     
  Branches     8410     8419       +9     
==========================================
+ Hits        48863    48873      +10     
  Misses       4061     4061              
- Partials     1358     1360       +2     

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[math-fehr]

Nice! I just had a comment with the name hint change, but otherwise that's perfect!

[math-fehr]

Can we have an option for changing the name?
Compared to replace_by, we don't change all uses, so we might run this function multiple times per value, making this name change a bit weird?

[superlopuh]

I doubt we'll ever hit the case you describe, it seems to be primarily useful for "replace everything except" as opposed to some targeted replacing. I'll merge this PR, and happily add an option if you are sure that it would be a good idea