[llvm] [RISCV] Improve cleanup phase of RISCV Insert VSETVLI pass (PR #67144)

[Ramkumar Ramachandra via llvm-commits]

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@@ -1458,8 +1458,10 @@ void RISCVInsertVSETVLI::doLocalPostpass(MachineBasicBlock &MBB) {
     if (VRegDef != RISCV::X0 &&
         !(VRegDef.isVirtual() && MRI->use_nodbg_empty(VRegDef))) {
       for (MachineInstr &UserMI : MRI->use_nodbg_instructions(VRegDef)) {
-        // ignore uses by *NextMI since we will deal with them explicitly
-        if (!NextMI || !UserMI.isIdenticalTo(*NextMI)) {
+        // do not track uses by *NextMI since we will deal with them explicitly,
+        // and also ignore uses by instructions that will be removed
+        if ((!NextMI || !UserMI.isIdenticalTo(*NextMI)) &&
+            ToDelete.find(&UserMI) == ToDelete.end()) {
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artagnon wrote:

Use `SmallPtrSet::contains()`.

https://github.com/llvm/llvm-project/pull/67144