Skip to content

DAG: Use poison when legalizing scalar_to_vector results #167751

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
Nov 15, 2025
+3 −3
Merged

DAG: Use poison when legalizing scalar_to_vector results #167751

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
c83e1c2
DAG: Use poison when legalizing scalar_to_vector results
arsenm Nov 12, 2025
2466334
Update documentation phrasing
arsenm Nov 12, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
4 changes: 2 additions & 2 deletions llvm/include/llvm/CodeGen/ISDOpcodes.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -655,8 +655,8 @@ enum NodeType {

/// SCALAR_TO_VECTOR(VAL) - This represents the operation of loading a
/// scalar value into element 0 of the resultant vector type. The top
/// elements 1 to N-1 of the N-element vector are undefined. The type
/// of the operand must match the vector element type, except when they
/// elements 1 to N-1 of the N-element vector are poison. The type of
/// the operand must match the vector element type, except when they
/// are integer types. In this case the operand is allowed to be wider
/// than the vector element type, and is implicitly truncated to it.
SCALAR_TO_VECTOR,
Expand Down
2 changes: 1 addition & 1 deletion llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2186,7 +2186,7 @@ void DAGTypeLegalizer::SplitVecRes_ScalarOp(SDNode *N, SDValue &Lo,
std::tie(LoVT, HiVT) = DAG.GetSplitDestVTs(N->getValueType(0));
Lo = DAG.getNode(N->getOpcode(), dl, LoVT, N->getOperand(0));
if (N->getOpcode() == ISD::SCALAR_TO_VECTOR) {
Hi = DAG.getUNDEF(HiVT);
Hi = DAG.getPOISON(HiVT);
} else {
assert(N->getOpcode() == ISD::SPLAT_VECTOR && "Unexpected opcode");
Hi = Lo;
Expand Down
Loading