[llvm] [ADT] Add implementations for avgFloor and ceilFloor to APInt (PR #84431)

[Jay Foad via llvm-commits]

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@@ -2193,6 +2193,18 @@ inline const APInt absdiff(const APInt &A, const APInt &B) {
   return A.uge(B) ? (A - B) : (B - A);
 }
 
+///.Compute the signed floor of the average of C1 and C2
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jayfoad wrote:

It is the average that is signed or unsigned, not the floor. So the comment should be "Compute the floor of the signed average of C1 and C2". Similarly for the others.

https://github.com/llvm/llvm-project/pull/84431