[PATCH] D20949: [AggressiveAntiDepBreaker] Don't change aliased registers of liveins to alive in StartBlock

[Hal Finkel via llvm-commits]

hfinkel added inline comments.

================
Comment at: lib/CodeGen/AggressiveAntiDepBreaker.cpp:153
@@ -152,7 +152,3 @@
     for (const auto &LI : (*SI)->liveins()) {
-      for (MCRegAliasIterator AI(LI.PhysReg, TRI, true); AI.isValid(); ++AI) {
-        unsigned Reg = *AI;
-        State->UnionGroups(Reg, 0);
-        KillIndices[Reg] = BB->size();
-        DefIndices[Reg] = ~0u;
-      }
+      unsigned Reg = LI.PhysReg;
+      State->UnionGroups(Reg, 0);
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Can you please add a comment here:

  // We only need to consider the live-out registers themselves, not all aliases, because...



http://reviews.llvm.org/D20949