Do not allow usage of reserved registers

Author: lei137

llvm/lib/Target/PowerPC/PPCISelLowering.cpp

@@ -17370,7 +17370,7 @@ SDValue PPCTargetLowering::LowerFRAMEADDR(SDValue Op,
 #define GET_REGISTER_MATCHER
 #include "PPCGenAsmMatcher.inc"
 
-Register PPCTargetLowering::getRegisterByName(const char* RegName, LLT VT,
+Register PPCTargetLowering::getRegisterByName(const char *RegName, LLT VT,
                                               const MachineFunction &MF) const {
 
   bool Is64Bit = Subtarget.isPPC64() && VT == LLT::scalar(64);
@@ -17379,15 +17379,15 @@ Register PPCTargetLowering::getRegisterByName(const char* RegName, LLT VT,
 
   Register Reg = MatchRegisterName(RegName);
   if (!Reg)
-    report_fatal_error(Twine("Invalid global name register \""
-                              + StringRef(RegName)  + "\"."));
+    report_fatal_error(
+        Twine("Invalid global name register \"" + StringRef(RegName) + "\"."));
 
   // Convert GPR to GP8R register for 64bit.
   if (Is64Bit && StringRef(RegName).starts_with_insensitive("r"))
     Reg = Reg.id() - PPC::R0 + PPC::X0;
 
   if (Subtarget.getRegisterInfo()->getReservedRegs(MF).test(Reg))
-    report_fatal_error(Twine("Trying to obtain non-reservable register \"" +
+    report_fatal_error(Twine("Trying to obtain a reserved register \"" +
                              StringRef(RegName) + "\"."));
   return Reg;
 }