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SIGEXTEND: first try [#81700414]

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This commit is contained in:
artur-zawlocki 2014-10-30 12:56:52 +00:00
parent af0530ba3d
commit 007641a84b
1 changed files with 33 additions and 4 deletions
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37
libevmjit/Compiler.cpp
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@ -372,14 +372,14 @@ void Compiler::compileBasicBlock(BasicBlock& basicBlock, bytesConstRef bytecode,
break;
}
/*case Instruction::NEG:
case Instruction::BNOT:
{
auto top = stack.pop();
auto zero = Constant::get(0);
auto res = m_builder.CreateSub(zero, top);
auto allones = llvm::ConstantInt::get(Type::i256, llvm::APInt::getAllOnesValue(256));
auto res = m_builder.CreateXor(top, allones);
stack.push(res);
break;
}*/
}
case Instruction::LT:
{
@ -505,6 +505,35 @@ void Compiler::compileBasicBlock(BasicBlock& basicBlock, bytesConstRef bytecode,
break;
}
case Instruction::SIGNEXTEND:
{
auto k = stack.pop();
auto b = stack.pop();
auto k32 = m_builder.CreateTrunc(k, m_builder.getIntNTy(5), "k_32");
auto k32ext = m_builder.CreateZExt(k32, Type::i256);
auto k32x8 = m_builder.CreateMul(k32ext, Constant::get(8), "kx8");
// test for b >> (k * 8 + 7)
auto val = m_builder.CreateAdd(k32x8, llvm::ConstantInt::get(Type::i256, 7));
auto tmp = m_builder.CreateAShr(b, val);
auto bitset = m_builder.CreateTrunc(tmp, m_builder.getInt1Ty());
// shift left by (31 - k) * 8 = (248 - k*8), then do arithmetic shr by the same amount.
auto shiftSize = m_builder.CreateSub(llvm::ConstantInt::get(Type::i256, 31 * 8), k32x8);
auto bshl = m_builder.CreateShl(b, shiftSize);
auto bshr = m_builder.CreateAShr(bshl, shiftSize);
// bshr is our final value if 0 <= k <= 30 and bitset is true,
// otherwise we push back b unchanged
auto kInRange = m_builder.CreateICmpULE(k, llvm::ConstantInt::get(Type::i256, 30));
auto cond = m_builder.CreateAnd(kInRange, bitset);
auto result = m_builder.CreateSelect(cond, bshr, b);
stack.push(result);
break;
}
case Instruction::SHA3:
{
auto inOff = stack.pop();