X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=lib%2FCodeGen%2FMachineCSE.cpp;h=896461fd194b52936db2b67755f419337cf91cfe;hb=e3d0e86919730784faaddcb5d9b0257c39b0804b;hp=5153abbc4e1160589ca47bc47923408d3b5ed4a2;hpb=39ad568c62f5120faec29f69d3d614303a1f992d;p=oota-llvm.git

diff --git a/lib/CodeGen/MachineCSE.cpp b/lib/CodeGen/MachineCSE.cpp
index 5153abbc4e1..896461fd194 100644
--- a/lib/CodeGen/MachineCSE.cpp
+++ b/lib/CodeGen/MachineCSE.cpp
@@ -215,8 +215,10 @@ bool MachineCSE::hasLivePhysRegDefUses(const MachineInstr *MI,
     if (MO.isDef() &&
         (MO.isDead() || isPhysDefTriviallyDead(Reg, I, MBB->end())))
       continue;
-    for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
-      PhysRefs.insert(*AI);
+    // Reading constant physregs is ok.
+    if (!MRI->isConstantPhysReg(Reg, *MBB->getParent()))
+      for (MCRegAliasIterator AI(Reg, TRI, true); AI.isValid(); ++AI)
+        PhysRefs.insert(*AI);
     if (MO.isDef())
       PhysDefs.push_back(Reg);
   }