[AVR] Remove SREG from CPI's Uses

[Florob]

Summary

CPI does not read the status register, but only writes it.

[dylanmckay]

Looks good to me, let me know if you need someone to commit it :)

[Florob]

Thank you for the review. Indeed I'd need someone to commit this.

lib/Target/AVR/AVRInstrInfo.td

let Defs = [SREG] in
   let Uses = [SREG] in
   def CPCWRdRr : Pseudo<(outs),
                         (ins DREGS:$src, DREGS:$src2),
                         "cpcw\t$src, $src2",
                         [(AVRcmpc i16:$src, i16:$src2), (implicit SREG)]>;
 
   // CPI Rd, K
   // Compares a register with an 8 bit immediate.
-  let Uses = [SREG] in
   def CPIRdK : FRdK<0b0011,
                     (outs),
                     (ins GPR8:$rd, imm_ldi8:$k),
                     "cpi\t$rd, $k",
                     [(AVRcmp i8:$rd, imm:$k), (implicit SREG)]>;
 }
 
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