[llvm] [LV] Create block in mask up-front if needed. (PR #76635)

[via llvm-commits]

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@@ -8026,8 +8029,9 @@ VPValue *VPRecipeBuilder::createBlockInMask(BasicBlock *BB, VPlan &Plan) {
   // This is the block mask. We OR all incoming edges.
   for (auto *Predecessor : predecessors(BB)) {
     VPValue *EdgeMask = createEdgeMask(Predecessor, BB, Plan);
-    if (!EdgeMask) // Mask of predecessor is all-one so mask of block is too.
-      return BlockMaskCache[BB] = EdgeMask;
+    if (!EdgeMask) { // Mask of predecessor is all-one so mask of block is too.
+      BlockMaskCache[BB] = EdgeMask;
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ayalz wrote:

Should retain early-exit and `return` here?

https://github.com/llvm/llvm-project/pull/76635