public void nestedBVEXTRACTVariableMiddle(int bitWidth)
{
Assert.IsTrue(bitWidth >= 3 && (bitWidth % 2 == 1));
var cfb = GetConstantFoldingBuilder();
var id = GetVarAndIdExpr("x", BasicType.GetBvType(bitWidth)).Item2;
Expr result = id;
// Keep peeling off the least significant bit and the most significant bit
// until we're only left the middle bit in the original "id"
for (int count = 0; count < bitWidth / 2; ++count)
{
int topBit = result.Type.BvBits - 1;
result = cfb.BVEXTRACT(result, topBit, 1);
CheckIsBvType(result, bitWidth - (2 * (count + 1)));
}
var asBvExtract = ExprUtil.AsBVEXTRACT(result);
Assert.IsNotNull(asBvExtract);
CheckIsBvType(asBvExtract, 1);
// Check there is only a single BvExtractExpr
Assert.AreSame(id, asBvExtract.Bitvector);
var middleBitIndex = bitWidth / 2;
Assert.AreEqual(middleBitIndex + 1, asBvExtract.End);
Assert.AreEqual(middleBitIndex, asBvExtract.Start);
}
public void nestedBVEXTRACTVariableEnd(int bitWidth)
{
var cfb = GetConstantFoldingBuilder();
var id = GetVarAndIdExpr("x", BasicType.GetBvType(bitWidth)).Item2;
Expr result = id;
// Keep peeling off the least significant bit until we're only left
// with the most significant bit
for (int count = 0; count < bitWidth - 1; ++count)
{
int topBitPlusOne = bitWidth - count;
result = cfb.BVEXTRACT(result, topBitPlusOne, 1);
CheckIsBvType(result, bitWidth - count - 1);
}
var asBvExtract = ExprUtil.AsBVEXTRACT(result);
Assert.IsNotNull(asBvExtract);
CheckIsBvType(asBvExtract, 1);
// Check there is only a single BvExtractExpr
Assert.AreSame(id, asBvExtract.Bitvector);
Assert.AreEqual(bitWidth, asBvExtract.End);
Assert.AreEqual(bitWidth - 1, asBvExtract.Start);
}
public void ConcatExtractsToSingleExtract()
{
var cfb = GetConstantFoldingBuilder();
var id = GetVarAndIdExpr("x", BasicType.GetBvType(16)).Item2;
var msb = cfb.BVEXTRACT(id, 16, 8);
var lsb = cfb.BVEXTRACT(id, 8, 5);
var result = cfb.BVCONCAT(msb, lsb);
CheckIsBvType(result, 11);
var asBvExtract = ExprUtil.AsBVEXTRACT(result);
Assert.IsNotNull(asBvExtract);
Assert.AreSame(id, asBvExtract.Bitvector);
Assert.AreEqual(16, asBvExtract.End);
Assert.AreEqual(5, asBvExtract.Start);
}
public void noFold()
{
var pair = GetSimpleAndConstantFoldingBuilder();
var sb = pair.Item1;
var cfb = pair.Item2;
var id = GetVarAndIdExpr("foo", BasicType.GetBvType(8)).Item2;
var foldedResult = cfb.BVEXTRACT(id, 7, 0);
var simpleResult = sb.BVEXTRACT(id, 7, 0);
CheckIsBvType(foldedResult, 7);
CheckIsBvType(simpleResult, 7);
Assert.AreEqual(simpleResult, foldedResult);
var asBvExtract = ExprUtil.AsBVEXTRACT(foldedResult);
Assert.IsNotNull(asBvExtract);
Assert.AreSame(id, asBvExtract.Bitvector);
Assert.AreEqual(0, asBvExtract.Start);
Assert.AreEqual(7, asBvExtract.End);
}