[PATCH] D84951: [LV] Try to sink users recursively for first-order recurrences.

[Ayal Zaks via Phabricator via llvm-commits]

Ayal added inline comments.


================
Comment at: llvm/lib/Transforms/Vectorize/LoopVectorize.cpp:9136
   // Apply Sink-After legal constraints.
-  for (auto &Entry : SinkAfter) {
+  for (auto &Entry : reverse(SinkAfter)) {
     VPRecipeBase *Sink = RecipeBuilder.getRecipe(Entry.first);
----------------
Ayal wrote:
> Sort multiple users in reverse instead of reversing all here? 
> Or rather - have them sink after each other instead of all sinking after Previous, thereby expressing their desired order and dependencies directly?
(BTW, note that by having multiple users sink after each other, it is also possible to reorder them lazily instead of sorting: when moving Sink after Target, check if Target should also be sunk - and if so sink it first, recursively, while taking care to sink each SinkAfter instruction once. Multiple users is the only exception to sinking an instruction after a Target that should itself sink.)


Repository:
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  https://reviews.llvm.org/D84951/new/

https://reviews.llvm.org/D84951