summaryrefslogtreecommitdiff
path: root/contrib/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGAddressAnalysis.cpp
diff options
context:
space:
mode:
Diffstat (limited to 'contrib/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGAddressAnalysis.cpp')
-rw-r--r--contrib/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGAddressAnalysis.cpp297
1 files changed, 297 insertions, 0 deletions
diff --git a/contrib/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGAddressAnalysis.cpp b/contrib/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGAddressAnalysis.cpp
new file mode 100644
index 000000000000..9592bc30a4e1
--- /dev/null
+++ b/contrib/llvm-project/llvm/lib/CodeGen/SelectionDAG/SelectionDAGAddressAnalysis.cpp
@@ -0,0 +1,297 @@
+//==- llvm/CodeGen/SelectionDAGAddressAnalysis.cpp - DAG Address Analysis --==//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#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(const BaseIndexOffset &Other,
+ const SelectionDAG &DAG,
+ int64_t &Off) const {
+ // Conservatively fail if we a match failed..
+ if (!Base.getNode() || !Other.Base.getNode())
+ return false;
+ if (!hasValidOffset() || !Other.hasValidOffset())
+ return false;
+ // 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;
+ }
+
+ // Match Constants
+ if (auto *A = dyn_cast<ConstantPoolSDNode>(Base))
+ if (auto *B = dyn_cast<ConstantPoolSDNode>(Other.Base)) {
+ bool IsMatch =
+ A->isMachineConstantPoolEntry() == B->isMachineConstantPoolEntry();
+ if (IsMatch) {
+ if (A->isMachineConstantPoolEntry())
+ IsMatch = A->getMachineCPVal() == B->getMachineCPVal();
+ else
+ IsMatch = A->getConstVal() == B->getConstVal();
+ }
+ if (IsMatch) {
+ Off += B->getOffset() - A->getOffset();
+ return true;
+ }
+ }
+
+ const MachineFrameInfo &MFI = DAG.getMachineFunction().getFrameInfo();
+
+ // Match FrameIndexes.
+ if (auto *A = dyn_cast<FrameIndexSDNode>(Base))
+ if (auto *B = dyn_cast<FrameIndexSDNode>(Other.Base)) {
+ // Equal FrameIndexes - offsets are directly comparable.
+ if (A->getIndex() == B->getIndex())
+ return true;
+ // Non-equal FrameIndexes - If both frame indices are fixed
+ // we know their relative offsets and can compare them. Otherwise
+ // we must be conservative.
+ if (MFI.isFixedObjectIndex(A->getIndex()) &&
+ MFI.isFixedObjectIndex(B->getIndex())) {
+ Off += MFI.getObjectOffset(B->getIndex()) -
+ MFI.getObjectOffset(A->getIndex());
+ return true;
+ }
+ }
+ }
+ return false;
+}
+
+bool BaseIndexOffset::computeAliasing(const SDNode *Op0,
+ const Optional<int64_t> NumBytes0,
+ const SDNode *Op1,
+ const Optional<int64_t> NumBytes1,
+ const SelectionDAG &DAG, bool &IsAlias) {
+
+ BaseIndexOffset BasePtr0 = match(Op0, DAG);
+ BaseIndexOffset BasePtr1 = match(Op1, DAG);
+
+ if (!(BasePtr0.getBase().getNode() && BasePtr1.getBase().getNode()))
+ return false;
+ int64_t PtrDiff;
+ if (NumBytes0.hasValue() && NumBytes1.hasValue() &&
+ BasePtr0.equalBaseIndex(BasePtr1, DAG, PtrDiff)) {
+ // BasePtr1 is PtrDiff away from BasePtr0. They alias if none of the
+ // following situations arise:
+ IsAlias = !(
+ // [----BasePtr0----]
+ // [---BasePtr1--]
+ // ========PtrDiff========>
+ (*NumBytes0 <= PtrDiff) ||
+ // [----BasePtr0----]
+ // [---BasePtr1--]
+ // =====(-PtrDiff)====>
+ (PtrDiff + *NumBytes1 <= 0)); // i.e. *NumBytes1 < -PtrDiff.
+ return true;
+ }
+ // If both BasePtr0 and BasePtr1 are FrameIndexes, we will not be
+ // able to calculate their relative offset if at least one arises
+ // from an alloca. However, these allocas cannot overlap and we
+ // can infer there is no alias.
+ if (auto *A = dyn_cast<FrameIndexSDNode>(BasePtr0.getBase()))
+ if (auto *B = dyn_cast<FrameIndexSDNode>(BasePtr1.getBase())) {
+ MachineFrameInfo &MFI = DAG.getMachineFunction().getFrameInfo();
+ // If the base are the same frame index but the we couldn't find a
+ // constant offset, (indices are different) be conservative.
+ if (A != B && (!MFI.isFixedObjectIndex(A->getIndex()) ||
+ !MFI.isFixedObjectIndex(B->getIndex()))) {
+ IsAlias = false;
+ return true;
+ }
+ }
+
+ bool IsFI0 = isa<FrameIndexSDNode>(BasePtr0.getBase());
+ bool IsFI1 = isa<FrameIndexSDNode>(BasePtr1.getBase());
+ bool IsGV0 = isa<GlobalAddressSDNode>(BasePtr0.getBase());
+ bool IsGV1 = isa<GlobalAddressSDNode>(BasePtr1.getBase());
+ bool IsCV0 = isa<ConstantPoolSDNode>(BasePtr0.getBase());
+ bool IsCV1 = isa<ConstantPoolSDNode>(BasePtr1.getBase());
+
+ // If of mismatched base types or checkable indices we can check
+ // they do not alias.
+ if ((BasePtr0.getIndex() == BasePtr1.getIndex() || (IsFI0 != IsFI1) ||
+ (IsGV0 != IsGV1) || (IsCV0 != IsCV1)) &&
+ (IsFI0 || IsGV0 || IsCV0) && (IsFI1 || IsGV1 || IsCV1)) {
+ IsAlias = false;
+ return true;
+ }
+ return false; // Cannot determine whether the pointers alias.
+}
+
+bool BaseIndexOffset::contains(const SelectionDAG &DAG, int64_t BitSize,
+ const BaseIndexOffset &Other,
+ int64_t OtherBitSize, int64_t &BitOffset) const {
+ int64_t Offset;
+ if (!equalBaseIndex(Other, DAG, Offset))
+ return false;
+ if (Offset >= 0) {
+ // Other is after *this:
+ // [-------*this---------]
+ // [---Other--]
+ // ==Offset==>
+ BitOffset = 8 * Offset;
+ return BitOffset + OtherBitSize <= BitSize;
+ }
+ // Other starts strictly before *this, it cannot be fully contained.
+ // [-------*this---------]
+ // [--Other--]
+ return false;
+}
+
+/// Parses tree in Ptr for base, index, offset addresses.
+static BaseIndexOffset matchLSNode(const LSBaseSDNode *N,
+ const SelectionDAG &DAG) {
+ SDValue Ptr = N->getBasePtr();
+
+ // (((B + I*M) + c)) + c ...
+ SDValue Base = DAG.getTargetLoweringInfo().unwrapAddress(Ptr);
+ SDValue Index = SDValue();
+ int64_t Offset = 0;
+ bool IsIndexSignExt = false;
+
+ // pre-inc/pre-dec ops are components of EA.
+ if (N->getAddressingMode() == ISD::PRE_INC) {
+ if (auto *C = dyn_cast<ConstantSDNode>(N->getOffset()))
+ Offset += C->getSExtValue();
+ else // If unknown, give up now.
+ return BaseIndexOffset(SDValue(), SDValue(), 0, false);
+ } else if (N->getAddressingMode() == ISD::PRE_DEC) {
+ if (auto *C = dyn_cast<ConstantSDNode>(N->getOffset()))
+ Offset -= C->getSExtValue();
+ else // If unknown, give up now.
+ return BaseIndexOffset(SDValue(), SDValue(), 0, false);
+ }
+
+ // Consume constant adds & ors with appropriate masking.
+ while (true) {
+ switch (Base->getOpcode()) {
+ case ISD::OR:
+ // Only consider ORs which act as adds.
+ if (auto *C = dyn_cast<ConstantSDNode>(Base->getOperand(1)))
+ if (DAG.MaskedValueIsZero(Base->getOperand(0), C->getAPIntValue())) {
+ Offset += C->getSExtValue();
+ Base = DAG.getTargetLoweringInfo().unwrapAddress(Base->getOperand(0));
+ continue;
+ }
+ break;
+ case ISD::ADD:
+ if (auto *C = dyn_cast<ConstantSDNode>(Base->getOperand(1))) {
+ Offset += C->getSExtValue();
+ Base = DAG.getTargetLoweringInfo().unwrapAddress(Base->getOperand(0));
+ continue;
+ }
+ break;
+ case ISD::LOAD:
+ case ISD::STORE: {
+ auto *LSBase = cast<LSBaseSDNode>(Base.getNode());
+ unsigned int IndexResNo = (Base->getOpcode() == ISD::LOAD) ? 1 : 0;
+ if (LSBase->isIndexed() && Base.getResNo() == IndexResNo)
+ if (auto *C = dyn_cast<ConstantSDNode>(LSBase->getOffset())) {
+ auto Off = C->getSExtValue();
+ if (LSBase->getAddressingMode() == ISD::PRE_DEC ||
+ LSBase->getAddressingMode() == ISD::POST_DEC)
+ Offset -= Off;
+ else
+ Offset += Off;
+ Base = DAG.getTargetLoweringInfo().unwrapAddress(LSBase->getBasePtr());
+ continue;
+ }
+ break;
+ }
+ }
+ // If we get here break out of the loop.
+ 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);
+}
+
+BaseIndexOffset BaseIndexOffset::match(const SDNode *N,
+ const SelectionDAG &DAG) {
+ if (const auto *LS0 = dyn_cast<LSBaseSDNode>(N))
+ return matchLSNode(LS0, DAG);
+ if (const auto *LN = dyn_cast<LifetimeSDNode>(N)) {
+ if (LN->hasOffset())
+ return BaseIndexOffset(LN->getOperand(1), SDValue(), LN->getOffset(),
+ false);
+ return BaseIndexOffset(LN->getOperand(1), SDValue(), false);
+ }
+ return BaseIndexOffset();
+}
+
+#if !defined(NDEBUG) || defined(LLVM_ENABLE_DUMP)
+
+LLVM_DUMP_METHOD void BaseIndexOffset::dump() const {
+ print(dbgs());
+}
+
+void BaseIndexOffset::print(raw_ostream& OS) const {
+ OS << "BaseIndexOffset base=[";
+ Base->print(OS);
+ OS << "] index=[";
+ if (Index)
+ Index->print(OS);
+ OS << "] offset=" << Offset;
+}
+
+#endif
generated by cgit v1.2.3 (git 2.25.1) at 2025-10-10 14:58:11 +0000