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c74bcc2521
AEABI defines aligned variants of memcpy etc. that can be faster than the default version due to not having to do alignment checks. When emitting target code for these functions make use of these aligned variants if possible. Also convert memset to memclr if possible. Differential Revision: http://reviews.llvm.org/D8060 llvm-svn: 237127
278 lines
9.6 KiB
C++
278 lines
9.6 KiB
C++
//===-- ARMSelectionDAGInfo.cpp - ARM SelectionDAG Info -------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements the ARMSelectionDAGInfo class.
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//
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//===----------------------------------------------------------------------===//
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#include "ARMTargetMachine.h"
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#include "llvm/CodeGen/SelectionDAG.h"
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#include "llvm/IR/DerivedTypes.h"
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using namespace llvm;
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#define DEBUG_TYPE "arm-selectiondag-info"
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ARMSelectionDAGInfo::ARMSelectionDAGInfo(const DataLayout &DL)
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: TargetSelectionDAGInfo(&DL) {}
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ARMSelectionDAGInfo::~ARMSelectionDAGInfo() {
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}
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// Emit, if possible, a specialized version of the given Libcall. Typically this
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// means selecting the appropriately aligned version, but we also convert memset
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// of 0 into memclr.
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SDValue ARMSelectionDAGInfo::
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EmitSpecializedLibcall(SelectionDAG &DAG, SDLoc dl,
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SDValue Chain,
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SDValue Dst, SDValue Src,
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SDValue Size, unsigned Align,
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RTLIB::Libcall LC) const {
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const ARMSubtarget &Subtarget =
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DAG.getMachineFunction().getSubtarget<ARMSubtarget>();
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const ARMTargetLowering *TLI = Subtarget.getTargetLowering();
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// Only use a specialized AEABI function if the default version of this
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// Libcall is an AEABI function.
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if (std::strncmp(TLI->getLibcallName(LC), "__aeabi", 7) != 0)
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return SDValue();
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// Translate RTLIB::Libcall to AEABILibcall. We only do this in order to be
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// able to translate memset to memclr and use the value to index the function
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// name array.
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enum {
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AEABI_MEMCPY = 0,
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AEABI_MEMMOVE,
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AEABI_MEMSET,
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AEABI_MEMCLR
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} AEABILibcall;
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switch (LC) {
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case RTLIB::MEMCPY:
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AEABILibcall = AEABI_MEMCPY;
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break;
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case RTLIB::MEMMOVE:
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AEABILibcall = AEABI_MEMMOVE;
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break;
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case RTLIB::MEMSET:
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AEABILibcall = AEABI_MEMSET;
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if (ConstantSDNode *ConstantSrc = dyn_cast<ConstantSDNode>(Src))
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if (ConstantSrc->getZExtValue() == 0)
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AEABILibcall = AEABI_MEMCLR;
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break;
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default:
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return SDValue();
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}
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// Choose the most-aligned libcall variant that we can
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enum {
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ALIGN1 = 0,
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ALIGN4,
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ALIGN8
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} AlignVariant;
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if ((Align & 7) == 0)
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AlignVariant = ALIGN8;
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else if ((Align & 3) == 0)
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AlignVariant = ALIGN4;
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else
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AlignVariant = ALIGN1;
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TargetLowering::ArgListTy Args;
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TargetLowering::ArgListEntry Entry;
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Entry.Ty = TLI->getDataLayout()->getIntPtrType(*DAG.getContext());
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Entry.Node = Dst;
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Args.push_back(Entry);
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if (AEABILibcall == AEABI_MEMCLR) {
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Entry.Node = Size;
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Args.push_back(Entry);
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} else if (AEABILibcall == AEABI_MEMSET) {
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// Adjust parameters for memset, EABI uses format (ptr, size, value),
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// GNU library uses (ptr, value, size)
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// See RTABI section 4.3.4
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Entry.Node = Size;
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Args.push_back(Entry);
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// Extend or truncate the argument to be an i32 value for the call.
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if (Src.getValueType().bitsGT(MVT::i32))
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Src = DAG.getNode(ISD::TRUNCATE, dl, MVT::i32, Src);
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else if (Src.getValueType().bitsLT(MVT::i32))
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Src = DAG.getNode(ISD::ZERO_EXTEND, dl, MVT::i32, Src);
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Entry.Node = Src;
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Entry.Ty = Type::getInt32Ty(*DAG.getContext());
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Entry.isSExt = false;
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Args.push_back(Entry);
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} else {
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Entry.Node = Src;
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Args.push_back(Entry);
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Entry.Node = Size;
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Args.push_back(Entry);
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}
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char const *FunctionNames[4][3] = {
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{ "__aeabi_memcpy", "__aeabi_memcpy4", "__aeabi_memcpy8" },
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{ "__aeabi_memmove", "__aeabi_memmove4", "__aeabi_memmove8" },
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{ "__aeabi_memset", "__aeabi_memset4", "__aeabi_memset8" },
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{ "__aeabi_memclr", "__aeabi_memclr4", "__aeabi_memclr8" }
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};
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TargetLowering::CallLoweringInfo CLI(DAG);
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CLI.setDebugLoc(dl).setChain(Chain)
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.setCallee(TLI->getLibcallCallingConv(LC),
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Type::getVoidTy(*DAG.getContext()),
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DAG.getExternalSymbol(FunctionNames[AEABILibcall][AlignVariant],
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TLI->getPointerTy()), std::move(Args), 0)
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.setDiscardResult();
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std::pair<SDValue,SDValue> CallResult = TLI->LowerCallTo(CLI);
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return CallResult.second;
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}
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SDValue
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ARMSelectionDAGInfo::EmitTargetCodeForMemcpy(SelectionDAG &DAG, SDLoc dl,
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SDValue Chain,
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SDValue Dst, SDValue Src,
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SDValue Size, unsigned Align,
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bool isVolatile, bool AlwaysInline,
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MachinePointerInfo DstPtrInfo,
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MachinePointerInfo SrcPtrInfo) const {
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const ARMSubtarget &Subtarget =
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DAG.getMachineFunction().getSubtarget<ARMSubtarget>();
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// Do repeated 4-byte loads and stores. To be improved.
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// This requires 4-byte alignment.
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if ((Align & 3) != 0)
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return SDValue();
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// This requires the copy size to be a constant, preferably
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// within a subtarget-specific limit.
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ConstantSDNode *ConstantSize = dyn_cast<ConstantSDNode>(Size);
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if (!ConstantSize)
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return EmitSpecializedLibcall(DAG, dl, Chain, Dst, Src, Size, Align,
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RTLIB::MEMCPY);
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uint64_t SizeVal = ConstantSize->getZExtValue();
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if (!AlwaysInline && SizeVal > Subtarget.getMaxInlineSizeThreshold())
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return EmitSpecializedLibcall(DAG, dl, Chain, Dst, Src, Size, Align,
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RTLIB::MEMCPY);
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unsigned BytesLeft = SizeVal & 3;
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unsigned NumMemOps = SizeVal >> 2;
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unsigned EmittedNumMemOps = 0;
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EVT VT = MVT::i32;
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unsigned VTSize = 4;
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unsigned i = 0;
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// Emit a maximum of 4 loads in Thumb1 since we have fewer registers
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const unsigned MAX_LOADS_IN_LDM = Subtarget.isThumb1Only() ? 4 : 6;
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SDValue TFOps[6];
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SDValue Loads[6];
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uint64_t SrcOff = 0, DstOff = 0;
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// Emit up to MAX_LOADS_IN_LDM loads, then a TokenFactor barrier, then the
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// same number of stores. The loads and stores will get combined into
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// ldm/stm later on.
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while (EmittedNumMemOps < NumMemOps) {
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for (i = 0;
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i < MAX_LOADS_IN_LDM && EmittedNumMemOps + i < NumMemOps; ++i) {
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Loads[i] = DAG.getLoad(VT, dl, Chain,
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DAG.getNode(ISD::ADD, dl, MVT::i32, Src,
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DAG.getConstant(SrcOff, dl, MVT::i32)),
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SrcPtrInfo.getWithOffset(SrcOff), isVolatile,
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false, false, 0);
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TFOps[i] = Loads[i].getValue(1);
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SrcOff += VTSize;
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}
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Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other,
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makeArrayRef(TFOps, i));
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for (i = 0;
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i < MAX_LOADS_IN_LDM && EmittedNumMemOps + i < NumMemOps; ++i) {
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TFOps[i] = DAG.getStore(Chain, dl, Loads[i],
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DAG.getNode(ISD::ADD, dl, MVT::i32, Dst,
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DAG.getConstant(DstOff, dl, MVT::i32)),
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DstPtrInfo.getWithOffset(DstOff),
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isVolatile, false, 0);
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DstOff += VTSize;
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}
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Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other,
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makeArrayRef(TFOps, i));
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EmittedNumMemOps += i;
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}
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if (BytesLeft == 0)
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return Chain;
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// Issue loads / stores for the trailing (1 - 3) bytes.
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unsigned BytesLeftSave = BytesLeft;
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i = 0;
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while (BytesLeft) {
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if (BytesLeft >= 2) {
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VT = MVT::i16;
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VTSize = 2;
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} else {
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VT = MVT::i8;
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VTSize = 1;
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}
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Loads[i] = DAG.getLoad(VT, dl, Chain,
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DAG.getNode(ISD::ADD, dl, MVT::i32, Src,
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DAG.getConstant(SrcOff, dl, MVT::i32)),
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SrcPtrInfo.getWithOffset(SrcOff),
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false, false, false, 0);
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TFOps[i] = Loads[i].getValue(1);
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++i;
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SrcOff += VTSize;
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BytesLeft -= VTSize;
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}
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Chain = DAG.getNode(ISD::TokenFactor, dl, MVT::Other,
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makeArrayRef(TFOps, i));
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i = 0;
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BytesLeft = BytesLeftSave;
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while (BytesLeft) {
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if (BytesLeft >= 2) {
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VT = MVT::i16;
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VTSize = 2;
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} else {
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VT = MVT::i8;
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VTSize = 1;
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}
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TFOps[i] = DAG.getStore(Chain, dl, Loads[i],
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DAG.getNode(ISD::ADD, dl, MVT::i32, Dst,
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DAG.getConstant(DstOff, dl, MVT::i32)),
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DstPtrInfo.getWithOffset(DstOff), false, false, 0);
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++i;
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DstOff += VTSize;
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BytesLeft -= VTSize;
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}
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return DAG.getNode(ISD::TokenFactor, dl, MVT::Other,
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makeArrayRef(TFOps, i));
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}
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SDValue ARMSelectionDAGInfo::
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EmitTargetCodeForMemmove(SelectionDAG &DAG, SDLoc dl,
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SDValue Chain,
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SDValue Dst, SDValue Src,
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SDValue Size, unsigned Align,
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bool isVolatile,
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MachinePointerInfo DstPtrInfo,
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MachinePointerInfo SrcPtrInfo) const {
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return EmitSpecializedLibcall(DAG, dl, Chain, Dst, Src, Size, Align,
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RTLIB::MEMMOVE);
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}
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SDValue ARMSelectionDAGInfo::
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EmitTargetCodeForMemset(SelectionDAG &DAG, SDLoc dl,
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SDValue Chain, SDValue Dst,
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SDValue Src, SDValue Size,
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unsigned Align, bool isVolatile,
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MachinePointerInfo DstPtrInfo) const {
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return EmitSpecializedLibcall(DAG, dl, Chain, Dst, Src, Size, Align,
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RTLIB::MEMSET);
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}
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