[llvm] LAA: refine condition for invariant stores (PR #124567)

[David Sherwood via llvm-commits]

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@@ -2545,7 +2545,8 @@ bool LoopAccessInfo::analyzeLoop(AAResults *AA, const LoopInfo *LI,
   for (StoreInst *ST : Stores) {
     Value *Ptr = ST->getPointerOperand();
 
-    if (isInvariant(Ptr)) {
+    const SCEV *PtrScev = replaceSymbolicStrideSCEV(*PSE, SymbolicStrides, Ptr);
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david-arm wrote:

The commit message says `use the information to refine the loop-invariant check`, but I can't think of any scenario where requiring a stride of 1 for the pointer would result in a different answer from `isLoopInvariant`. Prior to your change, when using a store pointer with a symbolic stride `isInvariant` would surely return false? With this patch applied the answer will still be false because now we know the stride is 1.

https://github.com/llvm/llvm-project/pull/124567