[llvm-branch-commits] [llvm] [LoopInterchange] Improve profitability check for vectorization (PR #133672)

[Sjoerd Meijer via llvm-branch-commits]

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@@ -80,6 +80,21 @@ enum class RuleTy {
   ForVectorization,
 };
 
+/// Store the information about if corresponding direction vector was negated
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sjoerdmeijer wrote:

Before I keep reading the rest of this patch, just wanted to share this first question that I had. I was initially a bit confused about this, and was wondering why we need 2 booleans and 4 states if a direction vector's negated status can only be true or false. But I now guess that the complication here is the unique entries in the dependency matrix, is that right? If that is the case, then I am wondering if it isn't easier to keep all the entries and don't make them unique? Making them unique was a little optimisation that I added recently because I thought that would help, but if this is now complicating things and we need to do all sorts of gymnastics we might as well keep all entries.

https://github.com/llvm/llvm-project/pull/133672