[llvm] [LV] Initial support for stores in early exit loops (PR #137774)

[Graham Hunter via llvm-commits]

================
@@ -1708,16 +1755,31 @@ bool LoopVectorizationLegality::isVectorizableEarlyExitLoop() {
     }
   };
 
+  bool HasStore = false;
   for (auto *BB : TheLoop->blocks())
     for (auto &I : *BB) {
+      if (StoreInst *SI = dyn_cast<StoreInst>(&I)) {
----------------
huntergr-arm wrote:

No. Since this prototype bails out to a scalar loop if the next vector iteration would exit partway through, it doesn't matter where the store is in the loop.

If/when we do tail-folding for these loops, we will need to generate different masks for state-changing operations before or after an exit.

https://github.com/llvm/llvm-project/pull/137774