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[SDAG] Introduce inbounds flag for pointer arithmetic #131862

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[SDAG] Introduce inbounds flag for pointer arithmetic #131862

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9 changes: 7 additions & 2 deletions llvm/include/llvm/CodeGen/SelectionDAGNodes.h
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Expand Up @@ -415,12 +415,15 @@ struct SDNodeFlags {
Unpredictable = 1 << 13,
// Compare instructions which may carry the samesign flag.
SameSign = 1 << 14,
// Pointer arithmetic instructions that remain in bounds, e.g., implementing
// an inbounds GEP.
InBounds = 1 << 15,

// NOTE: Please update LargestValue in LLVM_DECLARE_ENUM_AS_BITMASK below
// the class definition when adding new flags.

PoisonGeneratingFlags = NoUnsignedWrap | NoSignedWrap | Exact | Disjoint |
NonNeg | NoNaNs | NoInfs | SameSign,
NonNeg | NoNaNs | NoInfs | SameSign | InBounds,
FastMathFlags = NoNaNs | NoInfs | NoSignedZeros | AllowReciprocal |
AllowContract | ApproximateFuncs | AllowReassociation,
};
Expand Down Expand Up @@ -455,6 +458,7 @@ struct SDNodeFlags {
void setAllowReassociation(bool b) { setFlag<AllowReassociation>(b); }
void setNoFPExcept(bool b) { setFlag<NoFPExcept>(b); }
void setUnpredictable(bool b) { setFlag<Unpredictable>(b); }
void setInBounds(bool b) { setFlag<InBounds>(b); }

// These are accessors for each flag.
bool hasNoUnsignedWrap() const { return Flags & NoUnsignedWrap; }
Expand All @@ -472,6 +476,7 @@ struct SDNodeFlags {
bool hasAllowReassociation() const { return Flags & AllowReassociation; }
bool hasNoFPExcept() const { return Flags & NoFPExcept; }
bool hasUnpredictable() const { return Flags & Unpredictable; }
bool hasInBounds() const { return Flags & InBounds; }

bool operator==(const SDNodeFlags &Other) const {
return Flags == Other.Flags;
Expand All @@ -481,7 +486,7 @@ struct SDNodeFlags {
};

LLVM_DECLARE_ENUM_AS_BITMASK(decltype(SDNodeFlags::None),
SDNodeFlags::SameSign);
SDNodeFlags::InBounds);

inline SDNodeFlags operator|(SDNodeFlags LHS, SDNodeFlags RHS) {
LHS |= RHS;
Expand Down
3 changes: 3 additions & 0 deletions llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
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Expand Up @@ -4283,6 +4283,7 @@ void SelectionDAGBuilder::visitGetElementPtr(const User &I) {
if (NW.hasNoUnsignedWrap() ||
(int64_t(Offset) >= 0 && NW.hasNoUnsignedSignedWrap()))
Flags |= SDNodeFlags::NoUnsignedWrap;
Flags.setInBounds(NW.isInBounds());

N = DAG.getNode(ISD::ADD, dl, N.getValueType(), N,
DAG.getConstant(Offset, dl, N.getValueType()), Flags);
Expand Down Expand Up @@ -4326,6 +4327,7 @@ void SelectionDAGBuilder::visitGetElementPtr(const User &I) {
if (NW.hasNoUnsignedWrap() ||
(Offs.isNonNegative() && NW.hasNoUnsignedSignedWrap()))
Flags.setNoUnsignedWrap(true);
Flags.setInBounds(NW.isInBounds());

OffsVal = DAG.getSExtOrTrunc(OffsVal, dl, N.getValueType());

Expand Down Expand Up @@ -4388,6 +4390,7 @@ void SelectionDAGBuilder::visitGetElementPtr(const User &I) {
// pointer index type (add nuw).
SDNodeFlags AddFlags;
AddFlags.setNoUnsignedWrap(NW.hasNoUnsignedWrap());
AddFlags.setInBounds(NW.isInBounds());

N = DAG.getNode(ISD::ADD, dl, N.getValueType(), N, IdxN, AddFlags);
}
Expand Down
3 changes: 3 additions & 0 deletions llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
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Expand Up @@ -668,6 +668,9 @@ void SDNode::print_details(raw_ostream &OS, const SelectionDAG *G) const {
if (getFlags().hasSameSign())
OS << " samesign";

if (getFlags().hasInBounds())
OS << " inbounds";

if (getFlags().hasNonNeg())
OS << " nneg";

Expand Down
2 changes: 1 addition & 1 deletion llvm/test/CodeGen/X86/merge-store-partially-alias-loads.ll
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Expand Up @@ -16,7 +16,7 @@
; DBGDAG-LABEL: Optimized legalized selection DAG: %bb.0 'merge_store_partial_overlap_load:'
; DBGDAG: [[ENTRYTOKEN:t[0-9]+]]: ch,glue = EntryToken
; DBGDAG-DAG: [[BASEPTR:t[0-9]+]]: i64,ch = CopyFromReg [[ENTRYTOKEN]],
; DBGDAG-DAG: [[ADDPTR:t[0-9]+]]: i64 = add {{(nuw )?}}[[BASEPTR]], Constant:i64<2>
; DBGDAG-DAG: [[ADDPTR:t[0-9]+]]: i64 = add {{(nuw )?}}{{(inbounds )?}}[[BASEPTR]], Constant:i64<2>

; DBGDAG-DAG: [[LD2:t[0-9]+]]: i16,ch = load<(load (s16) from %ir.tmp81, align 1)> [[ENTRYTOKEN]], [[BASEPTR]], undef:i64
; DBGDAG-DAG: [[LD1:t[0-9]+]]: i8,ch = load<(load (s8) from %ir.tmp12)> [[ENTRYTOKEN]], [[ADDPTR]], undef:i64
Expand Down
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