[SystemZ] Reuse CC results for integer comparisons with zero

This also fixes a bug in the predication of LR to LOCR: I'd forgotten
that with these in-place instruction builds, the implicit operands need
to be added manually.  I think this was latent until now, but is tested
by int-cmp-45.c.  It also adds a CC valid mask to STOC, again tested by
int-cmp-45.c.

llvm-svn: 187573
diff --git a/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp b/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp
index 2b604a9..9913db7 100644
--- a/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp
+++ b/llvm/lib/Target/SystemZ/SystemZInstrInfo.cpp
@@ -341,7 +341,8 @@
     if (unsigned CondOpcode = getConditionalMove(Opcode)) {
       MI->setDesc(get(CondOpcode));
       MachineInstrBuilder(*MI->getParent()->getParent(), MI)
-        .addImm(CCValid).addImm(CCMask);
+        .addImm(CCValid).addImm(CCMask)
+        .addReg(SystemZ::CC, RegState::Implicit);;
       return true;
     }
   }