[PATCH] D57059: [SLP] Initial support for the vectorization of the non-power-of-2 vectors.

[Valeriy Dmitriev via Phabricator via llvm-commits]

vdmitrie added inline comments.


================
Comment at: llvm/lib/Transforms/Vectorize/SLPVectorizer.cpp:2761
+        if (Diff && ((NumberOfInstructions < VL.size() &&
+                      Diff->getAPInt().ule((VL.size() - 1) * Size)) ||
+                     (NumberOfInstructions == VL.size() &&
----------------
This check is not quite complete.
If we for example have following scalars set (VL)
0:  load  i32 from p[0]
1:  load i32 from p[2]
3: undef i32
4: undef i32
(note that p[1] is not loaded)

Pointers difference is 8, number of instructions is 2 and VL size is 4:
thus 8 <= (4 -1)*4 is true but pointers actually not loaded consecutively (although It is vectorizeable via masked load+shuffle but support seems not implemented yet). Similar issue exists for store.



Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D57059/new/

https://reviews.llvm.org/D57059