[llvm] [RISCV][VLOPT] Look through PHI instructions (PR #132236)

[Craig Topper via llvm-commits]

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@@ -1340,6 +1340,13 @@ RISCVVLOptimizer::checkUsers(const MachineInstr &MI) const {
       continue;
     }
 
+    if (UserMI.isPHI()) {
+      LLVM_DEBUG(dbgs() << "    Peeking through uses of PHI\n");
+      for (auto &PhiUse : MRI->use_operands(UserMI.getOperand(0).getReg()))
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topperc wrote:

Do we need to do anything to not go through a phi cycle indefinitely?

https://github.com/llvm/llvm-project/pull/132236