[llvm] [LAA] Hoist check for SCEV-uncomputable dist (NFC) (PR #148841)

[Igor Kirillov via llvm-commits]

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@@ -2085,6 +2085,12 @@ MemoryDepChecker::getDependenceDistanceStrideAndSize(
   if (!isa<SCEVConstant>(Dist))
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igogo-x86 wrote:

LGTM, but I realised one discrepancy.

If `isa<SCEVCouldNotCompute>(Dist)` is true, then this check is also true, and we may set FoundNonConstantDistanceDependence (which you rename to ShouldRetryWithRuntimeChecks). However, if there’s no dependence, which is determined later, we shouldn’t be doing this. That's out of the scope of the patch, so it may be worth fixing separately.

https://github.com/llvm/llvm-project/pull/148841