From 5a5ac124e1efaf208671f01c46edb15f29ed2a0b Mon Sep 17 00:00:00 2001
From: Dimitry Andric <dim@FreeBSD.org>
Date: Wed, 27 May 2015 18:44:32 +0000
Subject: Vendor import of llvm trunk r238337:
 https://llvm.org/svn/llvm-project/llvm/trunk@238337

---
 lib/CodeGen/AggressiveAntiDepBreaker.cpp | 10 ++++++++++
 1 file changed, 10 insertions(+)

(limited to 'lib/CodeGen/AggressiveAntiDepBreaker.cpp')

diff --git a/lib/CodeGen/AggressiveAntiDepBreaker.cpp b/lib/CodeGen/AggressiveAntiDepBreaker.cpp
index 69c368524a748..58b87e12912cf 100644
--- a/lib/CodeGen/AggressiveAntiDepBreaker.cpp
+++ b/lib/CodeGen/AggressiveAntiDepBreaker.cpp
@@ -296,6 +296,16 @@ void AggressiveAntiDepBreaker::HandleLastUse(unsigned Reg, unsigned KillIdx,
   std::multimap<unsigned, AggressiveAntiDepState::RegisterReference>&
     RegRefs = State->GetRegRefs();
 
+  // FIXME: We must leave subregisters of live super registers as live, so that
+  // we don't clear out the register tracking information for subregisters of
+  // super registers we're still tracking (and with which we're unioning
+  // subregister definitions).
+  for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
+    if (TRI->isSuperRegister(Reg, *AI) && State->IsLive(*AI)) {
+      DEBUG(if (!header && footer) dbgs() << footer);
+      return;
+    }
+
   if (!State->IsLive(Reg)) {
     KillIndices[Reg] = KillIdx;
     DefIndices[Reg] = ~0u;
-- 
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