This is an archive of the discontinued LLVM Phabricator instance.

In D57692#1383402, @niravd wrote:

Do we have a case where this changes things? because it looks like it should be already handled by the trivial Base == Other.Base check.

It does allow the comparison between FrameIndexSDNodes with the same FrameIndex, one being a TargetFrameIndex and the other one being a FrameIndex, which are essentially the same thing as far as BaseIndexOffset is concerned AFAICT (only the type of produced value differs).

I'm pretty sure they must be equivalent. I'm not sure if we can generate such a pattern, but the possiblity seems justification enough. Thanks.

This revision is now accepted and ready to land.Feb 4 2019, 12:50 PM

Thanks for the review !

Closed by commit rL353143: [DAG] BaseIndexOffset: FrameIndexSDNodes with the same FrameIndex compare equal. (authored by courbet). · Explain WhyFeb 4 2019, 11:36 PM

This revision was automatically updated to reflect the committed changes.

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lib/

CodeGen/

SelectionDAG/

SelectionDAGAddressAnalysis.cpp

14 lines

Diff 185060

lib/CodeGen/SelectionDAG/SelectionDAGAddressAnalysis.cpp

Show First 20 Lines • Show All 53 Lines • ▼ Show 20 Lines	if (auto *A = dyn_cast<ConstantPoolSDNode>(Base))
if (IsMatch) {		if (IsMatch) {
Off += B->getOffset() - A->getOffset();		Off += B->getOffset() - A->getOffset();
return true;		return true;
}		}
}		}

const MachineFrameInfo &MFI = DAG.getMachineFunction().getFrameInfo();		const MachineFrameInfo &MFI = DAG.getMachineFunction().getFrameInfo();

// Match non-equal FrameIndexes - If both frame indices are fixed		// 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 know their relative offsets and can compare them. Otherwise
// we must be conservative.		// we must be conservative.
if (auto *A = dyn_cast<FrameIndexSDNode>(Base))
if (auto *B = dyn_cast<FrameIndexSDNode>(Other.Base))
if (MFI.isFixedObjectIndex(A->getIndex()) &&		if (MFI.isFixedObjectIndex(A->getIndex()) &&
MFI.isFixedObjectIndex(B->getIndex())) {		MFI.isFixedObjectIndex(B->getIndex())) {
Off += MFI.getObjectOffset(B->getIndex()) -		Off += MFI.getObjectOffset(B->getIndex()) -
MFI.getObjectOffset(A->getIndex());		MFI.getObjectOffset(A->getIndex());
return true;		return true;
}		}
}		}
		}
return false;		return false;
}		}

/// Parses tree in Ptr for base, index, offset addresses.		/// Parses tree in Ptr for base, index, offset addresses.
BaseIndexOffset BaseIndexOffset::match(const LSBaseSDNode *N,		BaseIndexOffset BaseIndexOffset::match(const LSBaseSDNode *N,
const SelectionDAG &DAG) {		const SelectionDAG &DAG) {
SDValue Ptr = N->getBasePtr();		SDValue Ptr = N->getBasePtr();

▲ Show 20 Lines • Show All 108 Lines • ▼ Show 20 Lines	void BaseIndexOffset::print(raw_ostream& OS) const {
Base->print(OS);		Base->print(OS);
OS << "] index=[";		OS << "] index=[";
if (Index)		if (Index)
Index->print(OS);		Index->print(OS);
OS << "] offset=" << Offset;		OS << "] offset=" << Offset;
}		}

#endif		#endif

This is an archive of the discontinued LLVM Phabricator instance.

[DAG] BaseIndexOffset: FrameIndexSDNodes with the same FrameIndex compare equal.ClosedPublic

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Diff 185060

lib/CodeGen/SelectionDAG/SelectionDAGAddressAnalysis.cpp

[DAG] BaseIndexOffset: FrameIndexSDNodes with the same FrameIndex compare equal.
ClosedPublic