Fixed clang outputting extra byte '\7F' in clang test and fix a warning in SystemZISelLowering.cpp.

Author: anoopkg6

clang/lib/Basic/Targets/SystemZ.h

@@ -121,9 +121,10 @@ class LLVM_LIBRARY_VISIBILITY SystemZTargetInfo : public TargetInfo {
 
   std::string convertConstraint(const char *&Constraint) const override {
     if (llvm::StringRef(Constraint).starts_with("@cc")) {
+      auto Len = llvm::StringRef("@cc").size();
       std::string Converted =
-          std::string("{") + std::string("@cc") + std::string("}");
-      Constraint += 3;
+          std::string("{") + std::string(Constraint, Len) + std::string("}");
+      Constraint += Len - 1;
       return Converted;
     }
     switch (Constraint[0]) {

llvm/lib/Target/SystemZ/SystemZISelLowering.cpp

@@ -8012,6 +8012,10 @@ static bool combineCCIPMMask(SDValue &CCReg, int &CCValid, int &CCMask) {
           NewCCMask = NewCCMask1;
         else if (isSRL_IPM_CCSequence(AndOp2.getNode()) && IsOp2)
           NewCCMask = NewCCMask2;
+        else {
+          CCValid = RestoreCCValid;
+          return false;
+        }
         // Bit 29 set => CC == 2 || CC == 3.
         if ((NewCCMask & 0x3) == 2)
           NewCCMask = SystemZ::CCMASK_2 | SystemZ::CCMASK_3;