[PATCH] D44720: [clangd] Simplify fuzzy matcher (sequence alignment) by removing some condition checks.

[Fangrui Song via Phabricator via cfe-commits]

MaskRay added inline comments.


================
Comment at: clangd/FuzzyMatch.cpp:93
+  for (int I = PatN; I <= WordN; I++)
+    Best = std::max(Best, Scores[PatN][I][Match].Score);
   if (isAwful(Best))
----------------
sammccall wrote:
> MaskRay wrote:
> > sammccall wrote:
> > > this looks like a behavior change - why?
> > This is a behavior change. Instead of choosing between `Match/Miss` in the last position, we enumerate the last matching position in `Word`.
> > 
> > This saves `if (P < PatN - 1) {` check in the main loop at the cost of a for loop here (use sites of ending values)
> Ah, I see - the case where we match only part of the word is handled up here now.
> (I think you mean this is not a behavior change? The result is the same AFAICS)
> 
> That does make more sense, but it's pretty subtle.
> Can you add a comment like
>  `// The pattern doesn't have to match the whole word (but the whole pattern must match).`
Added
```
  // Find the optimal prefix of Word to match Pattern.
```

I meant this is a behavior change but it makes the first row and the rest rows of the score table more consistent.


Repository:
  rCTE Clang Tools Extra

https://reviews.llvm.org/D44720