Fix bug in commit 323096 exposed by test in test-suite-verify-machineinstrs-x86_64h-O3

Change-Id: I0a4b10d0d6c8de606d989c567ec07944ae283a87

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@323126 91177308-0d34-0410-b5e6-96231b3b80d8

Author: Marina Yatsina

lib/Target/X86/X86InstrInfo.cpp

@@ -8336,7 +8336,7 @@ void X86InstrInfo::breakPartialRegDependency(
     // Using XOR32rr because it has shorter encoding and zeros up the upper bits
     // as well.
     unsigned XReg = TRI->getSubReg(Reg, X86::sub_32bit);
-    BuildMI(*MI.getParent(), MI, MI.getDebugLoc(), get(X86::XOR32rr), Reg)
+    BuildMI(*MI.getParent(), MI, MI.getDebugLoc(), get(X86::XOR32rr), XReg)
         .addReg(XReg, RegState::Undef)
         .addReg(XReg, RegState::Undef)
         .addReg(Reg, RegState::ImplicitDefine);