[llvm] [LAA] Support different strides & non constant dep distances using SCEV. (PR #88039)

[Florian Hahn via llvm-commits]

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@@ -2028,68 +2029,105 @@ MemoryDepChecker::Dependence::DepType MemoryDepChecker::isDependent(
   if (std::holds_alternative<Dependence::DepType>(Res))
     return std::get<Dependence::DepType>(Res);
 
-  const auto &[Dist, Stride, TypeByteSize, AIsWrite, BIsWrite] =
+  const auto &[Dist, StrideA, StrideB, TypeByteSize, AIsWrite, BIsWrite] =
       std::get<DepDistanceStrideAndSizeInfo>(Res);
   bool HasSameSize = TypeByteSize > 0;
 
+  uint64_t CommonStride = StrideA == StrideB ? StrideA : 0;
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fhahn wrote:

At the moment, both strides need to be != 0 I think (`getDependenceDistanceStrideAndSize` returns `Unknown` dependence if any stride is == 0).

But using std::optional makes this future proof (I am planning to also remove that restriction as follow up), updated, thanks!

https://github.com/llvm/llvm-project/pull/88039