[llvm] [LoopVectorize] Perform loop versioning for some early exit loops (PR #120603)

[Paul Walker via llvm-commits]

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@@ -10542,8 +10611,19 @@ bool LoopVectorizePass::processLoop(Loop *L) {
     unsigned SelectedIC = std::max(IC, UserIC);
     //  Optimistically generate runtime checks if they are needed. Drop them if
     //  they turn out to not be profitable.
-    if (VF.Width.isVector() || SelectedIC > 1)
+    if (VF.Width.isVector() || SelectedIC > 1) {
+      if (LVL.getNumPotentiallyFaultingLoads()) {
+        assert(SelectedIC == 1 &&
+               "Interleaving not supported for early exit loops and "
+               "potentially faulting loads");
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paulwalker-arm wrote:

What makes interleaving problematic?  Would it be sufficient to ensure that when choosing combinations of VF and UF that the result of VFxUF is smaller than some safe value (i.e. essentially what you're doing for VF now but extended to VFxUF).

https://github.com/llvm/llvm-project/pull/120603