C++ (Cpp) GenTree::AsStoreInd Examples

Example #1

File: rationalize.cpp Project: bretambrose/coreclr

// Transform CopyBlk involving SIMD vectors into stlclvar or stind of a SIMD type.
// Transformation is done if either src or dst are known to be SIMD vectors.
//
// Arguments:
//    ppTree      - A pointer-to-a-pointer for the GT_COPYBLK
//    fgWalkData  - A pointer to tree walk data providing the context
//
// Return Value:
//    None.
//
// If either the source or the dst are known to be SIMD (a lclVar or SIMD intrinsic),
// get the simdType (TYP_DOUBLE or a SIMD type for SSE2) from the size of the SIMD node.
//
// For the source:
// - If it is a SIMD intrinsic or a lvSIMDType lclVar, change the node type to simdType.
// - Otherwise, add a GT_IND of simdType.
// For the dst:
// - If it is a lclVar of a SIMD type, chanage the node type to simdType.
// - Otherwise, change it to a GT_STORE_IND of simdType
//
// TODO-Cleanup: Once SIMD types are plumbed through the frontend, this will no longer
// be required.
//
void Rationalizer::RewriteCopyBlk(LIR::Use& use)
{
#ifdef FEATURE_SIMD
    // No need to transofrm non-SIMD nodes, if featureSIMD is not enabled.
    if (!comp->featureSIMD)
    {
        return;
    }

    // See if this is a SIMD copyBlk
    GenTreeCpBlk* cpBlk   = use.Def()->AsCpBlk();
    GenTreePtr    dstAddr = cpBlk->Dest();
    GenTree*      srcAddr = cpBlk->Source();

    const bool srcIsSIMDAddr = comp->isAddrOfSIMDType(srcAddr);
    const bool dstIsSIMDAddr = comp->isAddrOfSIMDType(dstAddr);

    // Do not transform if neither src or dst is known to be a SIMD type.
    // If src tree type is something we cannot reason but if dst is known to be of a SIMD type
    // we will treat src tree as a SIMD type and vice versa.
    if (!srcIsSIMDAddr && !dstIsSIMDAddr)
    {
        return;
    }

    // At this point it is known to be a copyblk of SIMD vectors and we can
    // start transforming the original tree. Prior to this point do not perform
    // any modifications to the original tree.
    JITDUMP("\nRewriting SIMD CopyBlk\n");
    DISPTREERANGE(BlockRange(), cpBlk);

    // There are currently only three sizes supported: 8 bytes, 12 bytes, 16 bytes or the vector register length.
    GenTreeIntConCommon* sizeNode = cpBlk->Size()->AsIntConCommon();
    var_types            simdType = comp->getSIMDTypeForSize((unsigned int)sizeNode->IconValue());

    // Remove 'size' from execution order
    BlockRange().Remove(sizeNode);

    // Is destination a lclVar which is not an arg?
    // If yes then we can turn it to a stlcl.var, otherwise turn into stind.
    GenTree*   simdDst = nullptr;
    genTreeOps oper    = GT_NONE;
    if (dstIsSIMDAddr && dstAddr->OperIsLocalAddr())
    {
        simdDst         = dstAddr;
        simdDst->gtType = simdType;
        oper            = GT_STORE_LCL_VAR;

        // For structs that are padded (e.g. Vector3f, Vector3i), the morpher will have marked them
        // as GTF_VAR_USEASG.  Unmark them.
        simdDst->gtFlags &= ~(GTF_VAR_USEASG);
    }
    else
    {
        // Address of a non-local var
        simdDst = dstAddr;
        oper    = GT_STOREIND;
    }

    GenTree* simdSrc = nullptr;
    if ((srcAddr->OperGet() == GT_ADDR) && varTypeIsSIMD(srcAddr->gtGetOp1()))
    {
        // Get rid of parent node of GT_ADDR(..) if its child happens to be of a SIMD type.
        BlockRange().Remove(srcAddr);
        simdSrc = srcAddr->gtGetOp1();
    }
    else if (srcIsSIMDAddr && srcAddr->OperIsLocalAddr())
    {
        // If the source has been rewritten into a local addr node, rewrite it back into a
        // local var node.
        simdSrc = srcAddr;
        simdSrc->SetOper(loadForm(srcAddr->OperGet()));
    }
    else
    {
        // Since destination is known to be a SIMD type, src must be a SIMD type too
        // though we cannot figure it out easily enough. Transform src into
        // GT_IND(src) of simdType.
        GenTree* indir = comp->gtNewOperNode(GT_IND, simdType, srcAddr);
        BlockRange().InsertAfter(srcAddr, indir);

        cpBlk->gtGetOp1()->gtOp.gtOp2 = indir;
        simdSrc                       = indir;
    }
    simdSrc->gtType = simdType;

    // Change cpblk to either a st.lclvar or st.ind.
    // At this point we are manipulating cpblk node with the knowledge of
    // its internals (i.e. op1 is the size node, and the src & dst are in a GT_LIST on op2).
    // This logic might need to be changed if we ever restructure cpblk node.

    assert(simdDst != nullptr);
    assert(simdSrc != nullptr);

    GenTree* newNode = nullptr;
    if (oper == GT_STORE_LCL_VAR)
    {
        newNode = simdDst;
        newNode->SetOper(oper);

        GenTreeLclVar* store = newNode->AsLclVar();
        store->gtOp1         = simdSrc;
        store->gtType        = simdType;
        store->gtFlags |= ((simdSrc->gtFlags & GTF_ALL_EFFECT) | GTF_ASG);

        BlockRange().Remove(simdDst);
        BlockRange().InsertAfter(simdSrc, store);
    }
    else
    {
        assert(oper == GT_STOREIND);

        newNode = cpBlk->gtGetOp1();
        newNode->SetOper(oper);

        GenTreeStoreInd* storeInd = newNode->AsStoreInd();
        storeInd->gtType          = simdType;
        storeInd->gtFlags |= ((simdSrc->gtFlags & GTF_ALL_EFFECT) | GTF_ASG);
        storeInd->gtOp1 = simdDst;
        storeInd->gtOp2 = simdSrc;

        BlockRange().InsertBefore(cpBlk, storeInd);
    }

    use.ReplaceWith(comp, newNode);
    BlockRange().Remove(cpBlk);

    JITDUMP("After rewriting SIMD CopyBlk:\n");
    DISPTREERANGE(BlockRange(), use.Def());
    JITDUMP("\n");
#endif // FEATURE_SIMD
}