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

[Graham Hunter via llvm-commits]

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@@ -1732,13 +1794,53 @@ bool LoopVectorizationLegality::isVectorizableEarlyExitLoop() {
 
   // TODO: Handle loops that may fault.
   Predicates.clear();
-  if (!isDereferenceableReadOnlyLoop(TheLoop, PSE.getSE(), DT, AC,
-                                     &Predicates)) {
+
+  if (HasStore && EELoad.has_value()) {
+    LoadInst *LI = *EELoad;
+    if (isDereferenceableAndAlignedInLoop(LI, TheLoop, *PSE.getSE(), *DT, AC,
+                                          &Predicates)) {
+      ICFLoopSafetyInfo SafetyInfo;
+      SafetyInfo.computeLoopSafetyInfo(TheLoop);
+      // FIXME: We may have multiple levels of conditional loads, so will
+      //        need to improve on outright rejection at some point.
+      if (!SafetyInfo.isGuaranteedToExecute(*LI, DT, TheLoop)) {
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huntergr-arm wrote:

More future work, hence the FIXME.

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