From fde221fa0a192a00dfdbce35ceec3d2035fe1019 Mon Sep 17 00:00:00 2001
From: Dan Gohman <gohman@apple.com>
Date: Tue, 16 Dec 2008 06:20:58 +0000
Subject: [PATCH] When breaking an anti-dependency, don't use a register which
 has seen one of its aliases defined. This is conservative, but tricky subreg
 corner cases are outside the primary aim of this pass.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@61077 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/CodeGen/PostRASchedulerList.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/CodeGen/PostRASchedulerList.cpp b/lib/CodeGen/PostRASchedulerList.cpp
index 0fc6c3370bb..865479d3006 100644
--- a/lib/CodeGen/PostRASchedulerList.cpp
+++ b/lib/CodeGen/PostRASchedulerList.cpp
@@ -454,6 +454,7 @@ bool SchedulePostRATDList::BreakAntiDependencies() {
         assert(((KillIndices[NewReg] == -1u) != (DefIndices[NewReg] == -1u)) &&
                "Kill and Def maps aren't consistent for NewReg!");
         if (KillIndices[NewReg] == -1u &&
+            Classes[NewReg] != reinterpret_cast<TargetRegisterClass *>(-1) &&
             KillIndices[AntiDepReg] <= DefIndices[NewReg]) {
           DOUT << "Breaking anti-dependence edge on "
                << TRI->getName(AntiDepReg)