[llvm] [Codegen] Remove redundant instruction using machinelateCleanup (PR #139716)

[Jay Foad via llvm-commits]

================
@@ -189,7 +189,13 @@ static bool isCandidate(const MachineInstr *MI, Register &DefedReg,
       if (MO.isDef()) {
         if (i == 0 && !MO.isImplicit() && !MO.isDead())
           DefedReg = MO.getReg();
-        else
+        else if (i != 0 && DefedReg != MCRegister::NoRegister) {
+          if (MO.isDead() && MO.isImplicit())
----------------
jayfoad wrote:

Example:
// If a later def is dead and implicit, ignore it.
Again I'm not sure why implicit matters.

https://github.com/llvm/llvm-project/pull/139716