[llvm] MachineLICM: Merge logic for implicit and explicit definitions. (PR #147624)

[Sergei Barannikov via llvm-commits]

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@@ -553,24 +553,14 @@ void MachineLICMImpl::ProcessMI(MachineInstr *MI, BitVector &RUDefs,
       continue;
     }
 
-    if (MO.isImplicit()) {
-      for (MCRegUnit Unit : TRI->regunits(Reg))
-        RUClobbers.set(Unit);
-      if (!MO.isDead())
-        // Non-dead implicit def? This cannot be hoisted.
+    // FIXME: For now, avoid instructions with multiple defs, unless it's dead.
+    if (!MO.isDead()) {
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s-barannikov wrote:

Can you please move the declaration of `Def` next to the FIXME? It is only used in this `if/else`.

https://github.com/llvm/llvm-project/pull/147624