private void EmitRangeCheckIfNeeded(ConstantValue startConstant, ConstantValue endConstant, object bucketFallThroughLabel)
{
// switch treats key as an unsigned int.
// this ensures that normalization does not introduce [over|under]flows issues with 32bit or shorter keys.
// 64bit values, however must be checked before 32bit truncation happens.
if (_keyTypeCode.Is64BitIntegral())
{
// Dup(normalized);
// if ((ulong)(normalized) > (ulong)(endConstant - startConstant))
// {
// // not going to use it in the switch
// Pop(normalized);
// goto bucketFallThroughLabel;
// }
var inRangeLabel = new object();
_builder.EmitOpCode(ILOpCode.Dup);
_builder.EmitLongConstant(endConstant.Int64Value - startConstant.Int64Value);
_builder.EmitBranch(ILOpCode.Ble_un, inRangeLabel, ILOpCode.Bgt_un);
_builder.EmitOpCode(ILOpCode.Pop);
_builder.EmitBranch(ILOpCode.Br, bucketFallThroughLabel);
// If we get to inRangeLabel, we should have key on stack, adjust for that.
// builder cannot infer this since it has not seen all branches,
// but it will verify that our Adjustment is valid when more branches are known.
_builder.AdjustStack(+1);
_builder.MarkLabel(inRangeLabel);
}
}
