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[RISCV] Fix the disassembler's handling of C.LUI when imm=0 #133450

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Merged
topperc merged 3 commits into from
Mar 28, 2025
Merged

[RISCV] Fix the disassembler's handling of C.LUI when imm=0 #133450

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29e4fcc
[riscv] Fix the disassembler's handling of C.LUI when imm=0
paulhuggett Mar 28, 2025
5e53b83
Drop braces, including the existing ones.
paulhuggett Mar 28, 2025
2a3c61f
Move the test to a more logical location and name.
paulhuggett Mar 28, 2025
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5 changes: 3 additions & 2 deletions llvm/lib/Target/RISCV/Disassembler/RISCVDisassembler.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -453,9 +453,10 @@ static DecodeStatus decodeCLUIImmOperand(MCInst &Inst, uint32_t Imm,
int64_t Address,
const MCDisassembler *Decoder) {
assert(isUInt<6>(Imm) && "Invalid immediate");
if (Imm > 31) {
if (Imm == 0)
return MCDisassembler::Fail;
if (Imm > 31)
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@topperc topperc Mar 28, 2025

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This Imm > 31 check seems unnecessary. SignExtend64<6> won't do anything to a number less than or equal to 31. But we don't have to change it in this patch.

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@paulhuggett paulhuggett Mar 28, 2025

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Interesting. A simple enough thing to check and change.

Imm = (SignExtend64<6>(Imm) & 0xfffff);
}
Inst.addOperand(MCOperand::createImm(Imm));
return MCDisassembler::Success;
}
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