本文整理汇总了C++中APInt::isSignBitSet方法的典型用法代码示例。如果您正苦于以下问题：C++ APInt::isSignBitSet方法的具体用法？C++ APInt::isSignBitSet怎么用？C++ APInt::isSignBitSet使用的例子？那么恭喜您, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类APInt的用法示例。
在下文中一共展示了APInt::isSignBitSet方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C++代码示例。
示例1: unknownResult
SymbolicValue
ConstExprFunctionState::computeConstantValueBuiltin(BuiltinInst *inst) {
const BuiltinInfo &builtin = inst->getBuiltinInfo();
// Handle various cases in groups.
auto unknownResult = [&]() -> SymbolicValue {
return evaluator.getUnknown(SILValue(inst), UnknownReason::Default);
};
// Unary operations.
if (inst->getNumOperands() == 1) {
auto operand = getConstantValue(inst->getOperand(0));
// TODO: Could add a "value used here" sort of diagnostic.
if (!operand.isConstant())
return operand;
// TODO: SUCheckedConversion/USCheckedConversion
// Implement support for s_to_s_checked_trunc_Int2048_Int64 and other
// checking integer truncates. These produce a tuple of the result value
// and an overflow bit.
//
// TODO: We can/should diagnose statically detectable integer overflow
// errors and subsume the ConstantFolding.cpp mandatory SIL pass.
auto IntCheckedTruncFn = [&](bool srcSigned,
bool dstSigned) -> SymbolicValue {
if (operand.getKind() != SymbolicValue::Integer)
return unknownResult();
auto operandVal = operand.getIntegerValue();
uint32_t srcBitWidth = operandVal.getBitWidth();
auto dstBitWidth =
builtin.Types[1]->castTo<BuiltinIntegerType>()->getGreatestWidth();
APInt result = operandVal.trunc(dstBitWidth);
// Compute the overflow by re-extending the value back to its source and
// checking for loss of value.
APInt reextended =
dstSigned ? result.sext(srcBitWidth) : result.zext(srcBitWidth);
bool overflowed = (operandVal != reextended);
if (!srcSigned && dstSigned)
overflowed |= result.isSignBitSet();
if (overflowed)
return evaluator.getUnknown(SILValue(inst), UnknownReason::Overflow);
auto &astContext = evaluator.getASTContext();
// Build the Symbolic value result for our truncated value.
return SymbolicValue::getAggregate(
{SymbolicValue::getInteger(result, astContext),
SymbolicValue::getInteger(APInt(1, overflowed), astContext)},
astContext);
};
switch (builtin.ID) {
default:
break;
case BuiltinValueKind::SToSCheckedTrunc:
return IntCheckedTruncFn(true, true);
case BuiltinValueKind::UToSCheckedTrunc:
return IntCheckedTruncFn(false, true);
case BuiltinValueKind::SToUCheckedTrunc:
return IntCheckedTruncFn(true, false);
case BuiltinValueKind::UToUCheckedTrunc:
return IntCheckedTruncFn(false, false);
case BuiltinValueKind::Trunc:
case BuiltinValueKind::TruncOrBitCast:
case BuiltinValueKind::ZExt:
case BuiltinValueKind::ZExtOrBitCast:
case BuiltinValueKind::SExt:
case BuiltinValueKind::SExtOrBitCast: {
if (operand.getKind() != SymbolicValue::Integer)
return unknownResult();
unsigned destBitWidth =
inst->getType().castTo<BuiltinIntegerType>()->getGreatestWidth();
APInt result = operand.getIntegerValue();
if (result.getBitWidth() != destBitWidth) {
switch (builtin.ID) {
default:
assert(0 && "Unknown case");
case BuiltinValueKind::Trunc:
case BuiltinValueKind::TruncOrBitCast:
result = result.trunc(destBitWidth);
break;
case BuiltinValueKind::ZExt:
case BuiltinValueKind::ZExtOrBitCast:
result = result.zext(destBitWidth);
break;
case BuiltinValueKind::SExt:
case BuiltinValueKind::SExtOrBitCast:
result = result.sext(destBitWidth);
break;
}
}
return SymbolicValue::getInteger(result, evaluator.getASTContext());
//.........这里部分代码省略.........