[SystemZ]: Remove incorrect CC use for C*BReturn instructions.

[• koriakin]

Summary

These are fused compare-and-branches, so they obviously don't use CC.

[uweigand]

LGTM, thanks. I'll apply it shortly.

lib/Target/SystemZ/SystemZInstrInfo.td

 let isReturn = 1, isTerminator = 1, isBarrier = 1, hasCtrlDep = 1 in
   def Return : Alias<2, (outs), (ins), [(z_retflag)]>;
 
 // A conditional return instruction (bcr <cond>, %r14).
 let isReturn = 1, isTerminator = 1, hasCtrlDep = 1, CCMaskFirst = 1, Uses = [CC] in
   def CondReturn : Alias<2, (outs), (ins cond4:$valid, cond4:$R1), []>;
 
 // Fused compare and conditional returns.
-let isReturn = 1, isTerminator = 1, hasCtrlDep = 1, Uses = [CC] in {
+let isReturn = 1, isTerminator = 1, hasCtrlDep = 1 in {
   def CRBReturn : Alias<6, (outs), (ins GR32:$R1, GR32:$R2, cond4:$M3), []>;
   def CGRBReturn : Alias<6, (outs), (ins GR64:$R1, GR64:$R2, cond4:$M3), []>;
   def CIBReturn : Alias<6, (outs), (ins GR32:$R1, imm32sx8:$I2, cond4:$M3), []>;
   def CGIBReturn : Alias<6, (outs), (ins GR64:$R1, imm64sx8:$I2, cond4:$M3), []>;
   def CLRBReturn : Alias<6, (outs), (ins GR32:$R1, GR32:$R2, cond4:$M3), []>;
   def CLGRBReturn : Alias<6, (outs), (ins GR64:$R1, GR64:$R2, cond4:$M3), []>;
   def CLIBReturn : Alias<6, (outs), (ins GR32:$R1, imm32zx8:$I2, cond4:$M3), []>;
   def CLGIBReturn : Alias<6, (outs), (ins GR64:$R1, imm64zx8:$I2, cond4:$M3), []>;