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llvm-mirror/lib/CodeGen/SelectionDAG/SelectionDAGAddressAnalysis.cpp
David Blaikie e01dc73ad2 Fix a bunch more layering of CodeGen headers that are in Target
All these headers already depend on CodeGen headers so moving them into
CodeGen fixes the layering (since CodeGen depends on Target, not the
other way around).

llvm-svn: 318490
2017-11-17 01:07:10 +00:00

117 lines
4.2 KiB
C++

//==- llvm/CodeGen/SelectionDAGAddressAnalysis.cpp - DAG Address Analysis --==//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/CodeGen/SelectionDAGAddressAnalysis.h"
#include "llvm/CodeGen/ISDOpcodes.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/SelectionDAG.h"
#include "llvm/CodeGen/SelectionDAGNodes.h"
#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/Support/Casting.h"
#include <cstdint>
using namespace llvm;
bool BaseIndexOffset::equalBaseIndex(BaseIndexOffset &Other,
const SelectionDAG &DAG, int64_t &Off) {
// Initial Offset difference.
Off = Other.Offset - Offset;
if ((Other.Index == Index) && (Other.IsIndexSignExt == IsIndexSignExt)) {
// Trivial match.
if (Other.Base == Base)
return true;
// Match GlobalAddresses
if (auto *A = dyn_cast<GlobalAddressSDNode>(Base))
if (auto *B = dyn_cast<GlobalAddressSDNode>(Other.Base))
if (A->getGlobal() == B->getGlobal()) {
Off += B->getOffset() - A->getOffset();
return true;
}
const MachineFrameInfo &MFI = DAG.getMachineFunction().getFrameInfo();
// Match non-equal FrameIndexes - If both frame indices are fixed
// we know their relative offsets and can compare them. Otherwise
// we must be conservative.
if (auto *A = dyn_cast<FrameIndexSDNode>(Base))
if (auto *B = dyn_cast<FrameIndexSDNode>(Other.Base))
if (MFI.isFixedObjectIndex(A->getIndex()) &&
MFI.isFixedObjectIndex(B->getIndex())) {
Off += MFI.getObjectOffset(B->getIndex()) -
MFI.getObjectOffset(A->getIndex());
return true;
}
}
return false;
}
/// Parses tree in Ptr for base, index, offset addresses.
BaseIndexOffset BaseIndexOffset::match(SDValue Ptr, const SelectionDAG &DAG) {
// (((B + I*M) + c)) + c ...
SDValue Base = DAG.getTargetLoweringInfo().unwrapAddress(Ptr);
SDValue Index = SDValue();
int64_t Offset = 0;
bool IsIndexSignExt = false;
// Consume constant adds & ors with appropriate masking.
while (Base->getOpcode() == ISD::ADD || Base->getOpcode() == ISD::OR) {
if (auto *C = dyn_cast<ConstantSDNode>(Base->getOperand(1))) {
// Only consider ORs which act as adds.
if (Base->getOpcode() == ISD::OR &&
!DAG.MaskedValueIsZero(Base->getOperand(0), C->getAPIntValue()))
break;
Offset += C->getSExtValue();
Base = Base->getOperand(0);
continue;
}
break;
}
if (Base->getOpcode() == ISD::ADD) {
// TODO: The following code appears to be needless as it just
// bails on some Ptrs early, reducing the cases where we
// find equivalence. We should be able to remove this.
// Inside a loop the current BASE pointer is calculated using an ADD and a
// MUL instruction. In this case Base is the actual BASE pointer.
// (i64 add (i64 %array_ptr)
// (i64 mul (i64 %induction_var)
// (i64 %element_size)))
if (Base->getOperand(1)->getOpcode() == ISD::MUL)
return BaseIndexOffset(Base, Index, Offset, IsIndexSignExt);
// Look at Base + Index + Offset cases.
Index = Base->getOperand(1);
SDValue PotentialBase = Base->getOperand(0);
// Skip signextends.
if (Index->getOpcode() == ISD::SIGN_EXTEND) {
Index = Index->getOperand(0);
IsIndexSignExt = true;
}
// Check if Index Offset pattern
if (Index->getOpcode() != ISD::ADD ||
!isa<ConstantSDNode>(Index->getOperand(1)))
return BaseIndexOffset(PotentialBase, Index, Offset, IsIndexSignExt);
Offset += cast<ConstantSDNode>(Index->getOperand(1))->getSExtValue();
Index = Index->getOperand(0);
if (Index->getOpcode() == ISD::SIGN_EXTEND) {
Index = Index->getOperand(0);
IsIndexSignExt = true;
} else
IsIndexSignExt = false;
Base = PotentialBase;
}
return BaseIndexOffset(Base, Index, Offset, IsIndexSignExt);
}