//------------------------------------------------------------------------
// DecomposeCast: Decompose GT_CAST.
//
// Arguments:
// use - the LIR::Use object for the def that needs to be decomposed.
//
// Return Value:
// The next node to process.
//
GenTree* DecomposeLongs::DecomposeCast(LIR::Use& use)
{
assert(use.IsInitialized());
assert(use.Def()->OperGet() == GT_CAST);
GenTree* tree = use.Def();
GenTree* loResult = nullptr;
GenTree* hiResult = nullptr;
assert(tree->gtPrev == tree->gtGetOp1());
NYI_IF(tree->gtOverflow(), "TYP_LONG cast with overflow");
switch (tree->AsCast()->CastFromType())
{
case TYP_INT:
if (tree->gtFlags & GTF_UNSIGNED)
{
loResult = tree->gtGetOp1();
Range().Remove(tree);
hiResult = new (m_compiler, GT_CNS_INT) GenTreeIntCon(TYP_INT, 0);
Range().InsertAfter(loResult, hiResult);
}
else
{
NYI("Lowering of signed cast TYP_INT->TYP_LONG");
}
break;
default:
NYI("Unimplemented type for Lowering of cast to TYP_LONG");
break;
}
return FinalizeDecomposition(use, loResult, hiResult);
}
//------------------------------------------------------------------------
// DecomposeCast: Decompose GT_CAST.
//
// Arguments:
// ppTree - the tree to decompose
// data - tree walk context
//
// Return Value:
// None.
//
void DecomposeLongs::DecomposeCast(GenTree** ppTree, Compiler::fgWalkData* data)
{
assert(ppTree != nullptr);
assert(*ppTree != nullptr);
assert(data != nullptr);
assert((*ppTree)->OperGet() == GT_CAST);
assert(m_compiler->compCurStmt != nullptr);
GenTree* tree = *ppTree;
GenTree* loResult = nullptr;
GenTree* hiResult = nullptr;
GenTreeStmt* curStmt = m_compiler->compCurStmt->AsStmt();
assert(tree->gtPrev == tree->gtGetOp1());
NYI_IF(tree->gtOverflow(), "TYP_LONG cast with overflow");
switch (tree->AsCast()->CastFromType())
{
case TYP_INT:
if (tree->gtFlags & GTF_UNSIGNED)
{
loResult = tree->gtGetOp1();
hiResult = new (m_compiler, GT_CNS_INT) GenTreeIntCon(TYP_INT, 0);
m_compiler->fgSnipNode(curStmt, tree);
}
else
{
NYI("Lowering of signed cast TYP_INT->TYP_LONG");
}
break;
default:
NYI("Unimplemented type for Lowering of cast to TYP_LONG");
break;
}
FinalizeDecomposition(ppTree, data, loResult, hiResult);
}
//------------------------------------------------------------------------
// DecomposeCast: Decompose GT_CAST.
//
// Arguments:
// use - the LIR::Use object for the def that needs to be decomposed.
//
// Return Value:
// The next node to process.
//
GenTree* DecomposeLongs::DecomposeCast(LIR::Use& use)
{
assert(use.IsInitialized());
assert(use.Def()->OperGet() == GT_CAST);
GenTree* cast = use.Def()->AsCast();
GenTree* loResult = nullptr;
GenTree* hiResult = nullptr;
var_types srcType = cast->CastFromType();
var_types dstType = cast->CastToType();
if ((cast->gtFlags & GTF_UNSIGNED) != 0)
{
srcType = genUnsignedType(srcType);
}
if (varTypeIsLong(srcType))
{
if (cast->gtOverflow() && (varTypeIsUnsigned(srcType) != varTypeIsUnsigned(dstType)))
{
GenTree* srcOp = cast->gtGetOp1();
noway_assert(srcOp->OperGet() == GT_LONG);
GenTree* loSrcOp = srcOp->gtGetOp1();
GenTree* hiSrcOp = srcOp->gtGetOp2();
//
// When casting between long types an overflow check is needed only if the types
// have different signedness. In both cases (long->ulong and ulong->long) we only
// need to check if the high part is negative or not. Use the existing cast node
// to perform a int->uint cast of the high part to take advantage of the overflow
// check provided by codegen.
//
loResult = loSrcOp;
hiResult = cast;
hiResult->gtType = TYP_INT;
hiResult->AsCast()->gtCastType = TYP_UINT;
hiResult->gtFlags &= ~GTF_UNSIGNED;
hiResult->gtOp.gtOp1 = hiSrcOp;
Range().Remove(cast);
Range().Remove(srcOp);
Range().InsertAfter(hiSrcOp, hiResult);
}
else
{
NYI("Unimplemented long->long no-op cast decomposition");
}
}
else if (varTypeIsIntegralOrI(srcType))
{
if (cast->gtOverflow() && !varTypeIsUnsigned(srcType) && varTypeIsUnsigned(dstType))
{
//
// An overflow check is needed only when casting from a signed type to ulong.
// Change the cast type to uint to take advantage of the overflow check provided
// by codegen and then zero extend the resulting uint to ulong.
//
loResult = cast;
loResult->AsCast()->gtCastType = TYP_UINT;
loResult->gtType = TYP_INT;
hiResult = m_compiler->gtNewZeroConNode(TYP_INT);
Range().InsertAfter(loResult, hiResult);
}
else
{
if (varTypeIsUnsigned(srcType))
{
loResult = cast->gtGetOp1();
hiResult = m_compiler->gtNewZeroConNode(TYP_INT);
Range().Remove(cast);
Range().InsertAfter(loResult, hiResult);
}
else
{
LIR::Use src(Range(), &(cast->gtOp.gtOp1), cast);
unsigned lclNum = src.ReplaceWithLclVar(m_compiler, m_blockWeight);
loResult = src.Def();
GenTree* loCopy = m_compiler->gtNewLclvNode(lclNum, TYP_INT);
GenTree* shiftBy = m_compiler->gtNewIconNode(31, TYP_INT);
hiResult = m_compiler->gtNewOperNode(GT_RSH, TYP_INT, loCopy, shiftBy);
Range().Remove(cast);
Range().InsertAfter(loResult, loCopy, shiftBy, hiResult);
m_compiler->lvaIncRefCnts(loCopy);
}
}
}
else
{
NYI("Unimplemented cast decomposition");
}
return FinalizeDecomposition(use, loResult, hiResult);
}