[llvm] [VPlan] Handle exit phis with multiple operands in addUsersInExitBlocks. (PR #120260)

[David Sherwood via llvm-commits]

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@@ -9025,22 +9034,23 @@ addUsersInExitBlocks(VPlan &Plan,
   // Introduce extract for exiting values and update the VPIRInstructions
   // modeling the corresponding LCSSA phis.
   for (VPIRInstruction *ExitIRI : ExitUsersToFix) {
-    VPValue *V = ExitIRI->getOperand(0);
-    // Pass live-in values used by exit phis directly through to their users in
-    // the exit block.
-    if (V->isLiveIn())
-      continue;
+    for (VPValue *Op : ExitIRI->operands()) {
+      // Pass live-in values used by exit phis directly through to their users
+      // in the exit block.
+      if (Op->isLiveIn())
+        continue;
 
-    // Currently only live-ins can be used by exit values from blocks not
-    // exiting via the vector latch through to the middle block.
-    if (ExitIRI->getParent()->getSinglePredecessor() != MiddleVPBB)
-      return false;
+      // Currently only live-ins can be used by exit values from blocks not
+      // exiting via the vector latch through to the middle block.
+      if (ExitIRI->getParent()->getSinglePredecessor() != MiddleVPBB)
+        return false;
 
-    LLVMContext &Ctx = ExitIRI->getInstruction().getContext();
-    VPValue *Ext = B.createNaryOp(VPInstruction::ExtractFromEnd,
-                                  {V, Plan.getOrAddLiveIn(ConstantInt::get(
-                                          IntegerType::get(Ctx, 32), 1))});
-    ExitIRI->setOperand(0, Ext);
+      LLVMContext &Ctx = ExitIRI->getInstruction().getContext();
+      VPValue *Ext = B.createNaryOp(VPInstruction::ExtractFromEnd,
+                                    {Op, Plan.getOrAddLiveIn(ConstantInt::get(
+                                             IntegerType::get(Ctx, 32), 1))});
+      ExitIRI->setOperand(0, Ext);
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david-arm wrote:

Should this be the index corresponding to the predecessor instead of 0? It doesn't matter for this patch I think, but I suppose it just looks a little odd that's all!

https://github.com/llvm/llvm-project/pull/120260