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[RISCV][RFC] Add additional opcodes to RISCVDAGToDAGISel::hasAllNBitUsers #147728

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[RISCV][RFC] Add additional opcodes to RISCVDAGToDAGISel::hasAllNBitUsers #147728

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31 changes: 29 additions & 2 deletions llvm/lib/Target/RISCV/RISCVISelDAGToDAG.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3606,11 +3606,15 @@ bool RISCVDAGToDAGISel::hasAllNBitUsers(SDNode *Node, unsigned Bits,
if (Use.getOperandNo() == 1 && Bits >= Log2_32(Subtarget->getXLen()))
break;
return false;
case RISCV::SLLI:
case RISCV::SLLI: {
// SLLI only uses the lower (XLen - ShAmt) bits.
if (Bits >= Subtarget->getXLen() - User->getConstantOperandVal(1))
uint64_t ShAmt = User->getConstantOperandVal(1);
if (Bits >= Subtarget->getXLen() - ShAmt)
break;
if (hasAllNBitUsers(User, Bits + ShAmt, Depth + 1))
break;
return false;
}
case RISCV::ANDI:
if (Bits >= (unsigned)llvm::bit_width(User->getConstantOperandVal(1)))
break;
Expand All @@ -3621,20 +3625,39 @@ bool RISCVDAGToDAGISel::hasAllNBitUsers(SDNode *Node, unsigned Bits,
break;
[[fallthrough]];
}
case RISCV::COPY:
case RISCV::PHI:
case RISCV::ADD:
case RISCV::ADDI:
case RISCV::AND:
case RISCV::MUL:
case RISCV::OR:
case RISCV::SUB:
case RISCV::XOR:
case RISCV::XORI:
case RISCV::ANDN:
case RISCV::BREV8:
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BREV8 and ORC_B are incorrect in RISCVOptWInstrs. We need to round to the nearest byte before doing the recursive call.

case RISCV::CLMUL:
case RISCV::ORC_B:
case RISCV::ORN:
case RISCV::XNOR:
case RISCV::SH1ADD:
case RISCV::SH2ADD:
case RISCV::SH3ADD:
case RISCV::BSETI:
case RISCV::BCLRI:
case RISCV::BINVI:
RecCheck:
if (hasAllNBitUsers(User, Bits, Depth + 1))
break;
return false;
case RISCV::CZERO_EQZ:
case RISCV::CZERO_NEZ:
if (Use.getOperandNo() != 0)
return false;
if (hasAllNBitUsers(User, Bits, Depth + 1))
break;
return false;
case RISCV::SRLI: {
unsigned ShAmt = User->getConstantOperandVal(1);
// If we are shifting right by less than Bits, and users don't demand any
Expand Down Expand Up @@ -3670,6 +3693,10 @@ bool RISCVDAGToDAGISel::hasAllNBitUsers(SDNode *Node, unsigned Bits,
if (Use.getOperandNo() == 0 && Bits >= 32)
break;
return false;
case RISCV::BEXTI:
if (User->getConstantOperandVal(1) >= Bits)
return false;
break;
case RISCV::SB:
if (Use.getOperandNo() == 0 && Bits >= 8)
break;
Expand Down
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