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[PowerPC] Remove non-existent operand of CP_COPY instruction #153867

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Sep 4, 2025
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[PowerPC] Remove non-existent operand of CP_COPY instruction #153867

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2 changes: 1 addition & 1 deletion llvm/lib/Target/PowerPC/PPCInstr64Bit.td
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Original file line number Diff line number Diff line change
Expand Up @@ -2000,7 +2000,7 @@ def : Pat<(int_ppc_darnraw), (DARN 2)>;

class X_RA5_RB5<bits<6> opcode, bits<10> xo, string opc, RegisterOperand ty,
InstrItinClass itin, list<dag> pattern>
: X_L1_RS5_RS5<opcode, xo, (outs), (ins ty:$RA, ty:$RB, u1imm:$L),
: X_L1_RS5_RS5<opcode, xo, (outs), (ins ty:$RA, ty:$RB),
!strconcat(opc, " $RA, $RB"), itin, pattern>{
let L = 1;
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This looks like it was meant to be used to generate the instr copy RA,RB,1.

In the class we have:

let Inst{10}    = L;

Even thought we set this explicitly to 1 on line 2005, I am not sure how that works.

I would think the generated instr needs to be fixed up here instead?

                 !strconcat(opc, " $RA, $RB, $L"), itin, pattern>{

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From what I could google, copy has only two operands. The L bit is bit 10, which has fixed value of 1 in the encoding.

Image

This is unlike paste instruction, which indeed has three operands:

Image

I guess you could call it a copy&paste bug 😆

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I was referring to Power ISA™ Version 3.1 (2020). In version 3.0 B (2017) paste is two operand as well.

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You are right! I was looking at an older ISA.

}
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