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[EVM][DAGCombine] Legalize brcond (i1 anything) #871

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github-actions bot commented Jul 30, 2025 •
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Results for: evm ir-llvm EVMInterpreter
╔═╡ Size (-%) ╞═══════════════════════╡ All E +M3B3 ╞═╗
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╠═╡ Cycles (-%) ╞═════════════════════╡ All E +M3B3 ╞═╣
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╠═╡ Ergs (-%) ╞═══════════════════════╡ All E +M3B3 ╞═╣
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╠══╡ Gas (-%) ╞═══════════════════════╡ All E +M3B3 ╞═╣
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╚═════════════════════════════════════════════════════╝

╔═╡ Size (-%) ╞═══════════════════════╡ All E +MzB3 ╞═╗
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╠═╡ Cycles (-%) ╞═════════════════════╡ All E +MzB3 ╞═╣
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╠═╡ Ergs (-%) ╞═══════════════════════╡ All E +MzB3 ╞═╣
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╠══╡ Gas (-%) ╞═══════════════════════╡ All E +MzB3 ╞═╣
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╚═════════════════════════════════════════════════════╝

╔═╡ Size (-%) ╞═══════════════════════╡ All Y +M3B3 ╞═╗
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╠═╡ Cycles (-%) ╞═════════════════════╡ All Y +M3B3 ╞═╣
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╠═╡ Ergs (-%) ╞═══════════════════════╡ All Y +M3B3 ╞═╣
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╠══╡ Gas (-%) ╞═══════════════════════╡ All Y +M3B3 ╞═╣
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╚═════════════════════════════════════════════════════╝

╔═╡ Size (-%) ╞═══════════════════════╡ All Y +MzB3 ╞═╗
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╠═╡ Cycles (-%) ╞═════════════════════╡ All Y +MzB3 ╞═╣
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╠═╡ Ergs (-%) ╞═══════════════════════╡ All Y +MzB3 ╞═╣
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╠══╡ Gas (-%) ╞═══════════════════════╡ All Y +MzB3 ╞═╣
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╚═════════════════════════════════════════════════════╝

╔═╡ Size (-%) ╞═════════════════╡ Real life E +M3B3 ╞═╗
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╠═╡ Cycles (-%) ╞═══════════════╡ Real life E +M3B3 ╞═╣
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╠═╡ Ergs (-%) ╞═════════════════╡ Real life E +M3B3 ╞═╣
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╠══╡ Gas (-%) ╞═════════════════╡ Real life E +M3B3 ╞═╣
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╚═════════════════════════════════════════════════════╝

╔═╡ Size (-%) ╞═════════════════╡ Real life E +MzB3 ╞═╗
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╠═╡ Cycles (-%) ╞═══════════════╡ Real life E +MzB3 ╞═╣
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╠═╡ Ergs (-%) ╞═════════════════╡ Real life E +MzB3 ╞═╣
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╠══╡ Gas (-%) ╞═════════════════╡ Real life E +MzB3 ╞═╣
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╚═════════════════════════════════════════════════════╝

╔═╡ Size (-%) ╞═════════════════╡ Real life Y +M3B3 ╞═╗
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╠═╡ Cycles (-%) ╞═══════════════╡ Real life Y +M3B3 ╞═╣
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╠═╡ Ergs (-%) ╞═════════════════╡ Real life Y +M3B3 ╞═╣
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╠══╡ Gas (-%) ╞═════════════════╡ Real life Y +M3B3 ╞═╣
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╚═════════════════════════════════════════════════════╝

╔═╡ Size (-%) ╞═════════════════╡ Real life Y +MzB3 ╞═╗
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╠═╡ Cycles (-%) ╞═══════════════╡ Real life Y +MzB3 ╞═╣
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╠═╡ Ergs (-%) ╞═════════════════╡ Real life Y +MzB3 ╞═╣
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╠══╡ Gas (-%) ╞═════════════════╡ Real life Y +MzB3 ╞═╣
║ Best                                          0.000 ║
║ Worst                                         0.000 ║
║ Total                                         0.000 ║
╚═════════════════════════════════════════════════════╝

@akiramenai akiramenai force-pushed the dborisenkov-legalizebrcondi1 branch from 8c6071c to 33d1895 Compare July 30, 2025 11:07
@akiramenai akiramenai marked this pull request as draft July 30, 2025 11:50
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Target Mode Toolchain Environment Link
eravm E+M3B3_0.4 ir-llvm zk_evm Results
eravm E+M3B3_0.5 ir-llvm zk_evm Results
eravm E+M3B3_0.6 ir-llvm zk_evm Results
eravm E+M3B3_0.7 ir-llvm zk_evm Results
eravm E+M3B3_0.8 ir-llvm zk_evm Results
eravm E+MzB3_0.4 ir-llvm zk_evm Results
eravm E+MzB3_0.5 ir-llvm zk_evm Results
eravm E+MzB3_0.6 ir-llvm zk_evm Results
eravm E+MzB3_0.7 ir-llvm zk_evm Results
eravm E+MzB3_0.8 ir-llvm zk_evm Results
eravm Y+M3B3 ir-llvm zk_evm Results
eravm Y+MzB3 ir-llvm zk_evm Results
evm E+M3B3 ir-llvm EVMInterpreter Results
evm E+MzB3 ir-llvm EVMInterpreter Results
evm Y+M3B3 ir-llvm EVMInterpreter Results
evm Y+MzB3 ir-llvm EVMInterpreter Results
evm E+_0.8 solc EVMInterpreter Results
evm Y+ solc EVMInterpreter Results

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📊 Excel Reports Available

solx: solx, LLVM-based Solidity compiler for the EVM v0.1.1, LLVM revision: v1.0.2, LLVM build: 3f2cb6119aafac3d5f34ab286e36a70110118121

llvm version: refs/pull/871/merge

solx version: main

The latest benchmark reports are ready for download and imported to Excel:

➡️ Download Excel Reports

Includes:

  • gas.xlsx
  • codesize.xlsx
  • compile-time.xlsx

@PavelKopyl PavelKopyl force-pushed the dborisenkov-legalizebrcondi1 branch from 33d1895 to 8d212b0 Compare August 18, 2025 21:06
@PavelKopyl PavelKopyl force-pushed the dborisenkov-legalizebrcondi1 branch from 8d212b0 to 3486c12 Compare August 18, 2025 21:28
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I've analyzed several failures and I’m not sure this approach works in the general case. To insert an any_extend before type legalization and DAG optimizations, we’d need to analyze the entire instruction tree used to build the condition for brcond and ensure that only LBS bit is used. The problem, as I see it now, is that such analysis won’t remain valid after type legalization (i1 -> i256). ISel will optimize the DAG differently depending on whether zext or anyext is used, effectively changing the semantics of the original code.
The only viable option is to perform combining right before the instruction selection stage itself, that is, when and i256 1, %x has already been inserted, and we’re trying to remove it. However, this patch doesn’t yield any improvements in compiler-tester, with the only observed case being when a function has an argument of type i1. It seems to me that in all other cases the DAG either doesn’t insert an and for the branch condition, or those ands are actually required.

Here is an example when AND is redundant:

define void @dont_trunc_or_cond(i256 %a, i1 %conda) {
  %cond = icmp ne i256 %a, 0
  %condb = or i1 %cond, %conda
  br i1 %condb, label %true, label %false
false:
  unreachable
true:
  unreachable
}

dont_trunc_or_cond:                     ; @dont_trunc_or_cond
; %bb.0:
	JUMPDEST
	PUSH1           0x1
	SWAP3
	POP
	ISZERO
	ISZERO
	OR
	AND
	PUSH4           @.BB0_2
	JUMPI
; %bb.1:                                ; %false
.BB0_2:                                 ; %true
	JUMPDEST
                                        ; -- End function
	INVALID

This AND can be eliminated, for example, by following change in ISel:

SDValue EVMTargetLowering::combineBRCOND(SDNode *N,
                                         DAGCombinerInfo &DCI) const {
  // Perform combines only after DAG legalisation.
  if (!DCI.isAfterLegalizeDAG())
    return SDValue();

  SDLoc DL(N);
  SelectionDAG &DAG = DCI.DAG;
  assert(N->getOpcode() == ISD::BRCOND);
  SDValue Chain = N->getOperand(0);
  SDValue Cond = N->getOperand(1);
  SDValue Dest = N->getOperand(2);

  SDNode *CondNode = Cond.getNode();
  if (CondNode->getOpcode() != ISD::AND)
    return SDValue();

  if (!isa<ConstantSDNode>(CondNode->getOperand(0)) &&
      !isa<ConstantSDNode>(CondNode->getOperand(1)))
    return SDValue();

  unsigned AndConstOpIdx = isa<ConstantSDNode>(CondNode->getOperand(0)) ? 0 : 1;
  if (auto *C = cast<ConstantSDNode>(CondNode->getOperand(AndConstOpIdx));
      !C->getAPIntValue().isOne())
    return SDValue();

  SDValue AndNonConstOp = CondNode->getOperand(!AndConstOpIdx);
  SmallVector<SDNode *, 64> Worklist;
  Worklist.push_back(AndNonConstOp.getNode());

  const Function &F = DAG.getMachineFunction().getFunction();
  while (!Worklist.empty()) {
    SDNode *Node = Worklist.pop_back_val();
    unsigned Opcode = Node->getOpcode();

    if (Opcode == ISD::SETCC)
      continue;

    if (Opcode == EVMISD::ARGUMENT) {
      unsigned ArgIdx = Node->getConstantOperandVal(0);
      Type *ArgTy = F.getArg(ArgIdx)->getType();
      if (ArgTy->isIntegerTy() && ArgTy->getIntegerBitWidth() == 1)
        continue;
    }

    if (Opcode == ISD::AND) {
      for (const SDValue &Op : Node->op_values())
        if (auto *C = dyn_cast<ConstantSDNode>(Op); C->getAPIntValue().isOne())
          continue;
    }

    if (Opcode == ISD::Constant)
      if (!cast<ConstantSDNode>(Node)->getAPIntValue().isOne())
        continue;

    if (Opcode != ISD::AND && Opcode != ISD::OR && Opcode != ISD::XOR)
      return SDValue();

    for (const SDValue &Op : Node->op_values())
      Worklist.push_back(Op.getNode());
  }

  // Rebuild BRCOND as BRCOND.chain, Ext:i256, Dest
  return DAG.getNode(ISD::BRCOND, DL, MVT::Other, Chain, AndNonConstOp, Dest);
}

@PavelKopyl PavelKopyl closed this Aug 21, 2025
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@akiramenai @PavelKopyl