diff --git a/lib/CodeGen/TwoAddressInstructionPass.cpp b/lib/CodeGen/TwoAddressInstructionPass.cpp
index 8a18dc0fc79..42d517b2e5f 100644
--- a/lib/CodeGen/TwoAddressInstructionPass.cpp
+++ b/lib/CodeGen/TwoAddressInstructionPass.cpp
@@ -405,7 +405,7 @@ static
 MachineInstr *findOnlyInterestingUse(unsigned Reg, MachineBasicBlock *MBB,
                                      MachineRegisterInfo *MRI,
                                      const TargetInstrInfo *TII,
-                                     bool &isCopy,
+                                     bool &IsCopy,
                                      unsigned &DstReg, bool &IsDstPhys) {
   MachineRegisterInfo::use_iterator UI = MRI->use_begin(Reg);
   if (UI == MRI->use_end())
@@ -418,11 +418,15 @@ MachineInstr *findOnlyInterestingUse(unsigned Reg, MachineBasicBlock *MBB,
     return 0;
   unsigned SrcReg;
   bool IsSrcPhys;
-  if (isCopyToReg(UseMI, TII, SrcReg, DstReg, IsSrcPhys, IsDstPhys))
+  if (isCopyToReg(UseMI, TII, SrcReg, DstReg, IsSrcPhys, IsDstPhys)) {
+    IsCopy = true;
     return &UseMI;
+  }
   IsDstPhys = false;
-  if (isTwoAddrUse(UseMI, Reg, DstReg))
+  if (isTwoAddrUse(UseMI, Reg, DstReg)) {
+    IsDstPhys = TargetRegisterInfo::isPhysicalRegister(DstReg);
     return &UseMI;
+  }
   return 0;
 }
 
@@ -634,12 +638,12 @@ void TwoAddressInstructionPass::ProcessCopy(MachineInstr *MI,
              "Can't map to two src physical registers!");
 
     SmallVector<unsigned, 4> VirtRegPairs;
-    bool isCopy = false;
+    bool IsCopy = false;
     unsigned NewReg = 0;
     while (MachineInstr *UseMI = findOnlyInterestingUse(DstReg, MBB, MRI,TII,
-                                                   isCopy, NewReg, IsDstPhys)) {
-      if (isCopy) {
-        if (Processed.insert(UseMI))
+                                                   IsCopy, NewReg, IsDstPhys)) {
+      if (IsCopy) {
+        if (!Processed.insert(UseMI))
           break;
       }
 
@@ -654,8 +658,8 @@ void TwoAddressInstructionPass::ProcessCopy(MachineInstr *MI,
       }
       bool isNew = SrcRegMap.insert(std::make_pair(NewReg, DstReg)).second;
       if (!isNew)
-      assert(SrcRegMap[NewReg] == DstReg &&
-             "Can't map to two src physical registers!");
+        assert(SrcRegMap[NewReg] == DstReg &&
+               "Can't map to two src physical registers!");
       VirtRegPairs.push_back(NewReg);
       DstReg = NewReg;
     }
diff --git a/test/CodeGen/X86/2009-04-13-2AddrAssert-2.ll b/test/CodeGen/X86/2009-04-13-2AddrAssert-2.ll
new file mode 100644
index 00000000000..d6f4b9444b5
--- /dev/null
+++ b/test/CodeGen/X86/2009-04-13-2AddrAssert-2.ll
@@ -0,0 +1,15 @@
+; RUN: llvm-as < %s | llc -mtriple=i386-apple-darwin
+; rdar://6781755
+; PR3934
+
+	type { i32, i32 }		; type %0
+
+define void @bn_sqr_comba8(i32* nocapture %r, i32* %a) nounwind {
+entry:
+	%asmtmp23 = tail call %0 asm "mulq $3", "={ax},={dx},{ax},*m,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 0, i32* %a) nounwind		; <%0> [#uses=1]
+	%asmresult25 = extractvalue %0 %asmtmp23, 1		; <i32> [#uses=1]
+	%asmtmp26 = tail call %0 asm "addq $0,$0; adcq $2,$1", "={dx},=r,imr,0,1,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 0, i32 %asmresult25, i32 0) nounwind		; <%0> [#uses=1]
+	%asmresult27 = extractvalue %0 %asmtmp26, 0		; <i32> [#uses=1]
+	%asmtmp29 = tail call %0 asm "addq $0,$0; adcq $2,$1", "={ax},={dx},imr,0,1,~{dirflag},~{fpsr},~{flags},~{cc}"(i32 0, i32 0, i32 %asmresult27) nounwind		; <%0> [#uses=0]
+	ret void
+}
diff --git a/test/CodeGen/X86/subreg-to-reg-1.ll b/test/CodeGen/X86/subreg-to-reg-1.ll
index cf9f2d81425..aa26f06aba9 100644
--- a/test/CodeGen/X86/subreg-to-reg-1.ll
+++ b/test/CodeGen/X86/subreg-to-reg-1.ll
@@ -5,7 +5,7 @@
 ; though this isn't necessary; The point of this test is to make sure
 ; a 32-bit add is used.
 
-define i64 @foo(i64 %a) {
+define i64 @foo(i64 %a) nounwind {
   %b = add i64 %a, 4294967295
   %c = and i64 %b, 4294967295
   %d = add i64 %c, 1