[PATCH] D133524: [SLP]Improve reordering of clustered reused scalars.

[Valeriy Dmitriev via Phabricator via llvm-commits]

vdmitrie added inline comments.


================
Comment at: llvm/lib/IR/Instructions.cpp:2576
+    return false;
+  // If each index is used just once, the sum of such indices is VF * (VF - 1) /
+  // 2 - arithmetic sequence.
----------------
I wonder why you departed from BitVector approach you used in the previous revision?
The above statement is true. But what you are doing here is applying the opposite statement
(if sum is VF * (VF-1)/2  then each index is used once in each submask).

If we have mask "0222 0123" and VF==4 the sum will be 6 in both submasks.



Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D133524/new/

https://reviews.llvm.org/D133524