Skip to content

[LLVM][SelectionDAG] Ensure Constant[FP]SDnode only store references to scalar Constant{Int,FP}. #111005

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
Oct 15, 2024
Merged

[LLVM][SelectionDAG] Ensure Constant[FP]SDnode only store references to scalar Constant{Int,FP}. #111005

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
43daf9c
[LLVM][SelectionDAG] Ensure Constant[FP]SDnode only store references …
paulwalker-arm Oct 1, 2024
3f9b0bf
Update comment.
paulwalker-arm Oct 10, 2024
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
5 changes: 4 additions & 1 deletion llvm/include/llvm/CodeGen/SelectionDAGNodes.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1678,6 +1678,7 @@ class ConstantSDNode : public SDNode {
: SDNode(isTarget ? ISD::TargetConstant : ISD::Constant, 0, DebugLoc(),
VTs),
Value(val) {
assert(!isa<VectorType>(val->getType()) && "Unexpected vector type!");
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

This is just a thought, but is it worth tying these asserts down even further, i.e.

assert(val->getType()->isIntegerTy() && "Unexpected type!");

and similarly for the FP node? At the moment, these nodes still won't assert for any other unusual types.

Copy link
Collaborator Author

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

That's handled as part of ConstantInt construction and thus here we can safely assume val has a valid type for its class.

ConstantSDNodeBits.IsOpaque = isOpaque;
}

Expand Down Expand Up @@ -1730,7 +1731,9 @@ class ConstantFPSDNode : public SDNode {
ConstantFPSDNode(bool isTarget, const ConstantFP *val, SDVTList VTs)
: SDNode(isTarget ? ISD::TargetConstantFP : ISD::ConstantFP, 0,
DebugLoc(), VTs),
Value(val) {}
Value(val) {
assert(!isa<VectorType>(val->getType()) && "Unexpected vector type!");
}

public:
const APFloat& getValueAPF() const { return Value->getValueAPF(); }
Expand Down
15 changes: 13 additions & 2 deletions llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1656,6 +1656,11 @@ SDValue SelectionDAG::getConstant(const ConstantInt &Val, const SDLoc &DL,
EVT EltVT = VT.getScalarType();
const ConstantInt *Elt = &Val;

// Vector splats are explicit within the DAG, with ConstantSDNode holding the
// to-be-splatted scalar ConstantInt.
if (isa<VectorType>(Elt->getType()))
Elt = ConstantInt::get(*getContext(), Elt->getValue());

// In some cases the vector type is legal but the element type is illegal and
// needs to be promoted, for example v8i8 on ARM. In this case, promote the
// inserted value (the type does not need to match the vector element type).
Expand Down Expand Up @@ -1809,6 +1814,12 @@ SDValue SelectionDAG::getConstantFP(const ConstantFP &V, const SDLoc &DL,
assert(VT.isFloatingPoint() && "Cannot create integer FP constant!");

EVT EltVT = VT.getScalarType();
const ConstantFP *Elt = &V;

// Vector splats are explicit within the DAG, with ConstantFPSDNode holding
// the to-be-splatted scalar ConstantFP.
if (isa<VectorType>(Elt->getType()))
Elt = ConstantFP::get(*getContext(), Elt->getValue());

// Do the map lookup using the actual bit pattern for the floating point
// value, so that we don't have problems with 0.0 comparing equal to -0.0, and
Expand All @@ -1817,15 +1828,15 @@ SDValue SelectionDAG::getConstantFP(const ConstantFP &V, const SDLoc &DL,
SDVTList VTs = getVTList(EltVT);
FoldingSetNodeID ID;
AddNodeIDNode(ID, Opc, VTs, {});
ID.AddPointer(&V);
ID.AddPointer(Elt);
void *IP = nullptr;
SDNode *N = nullptr;
if ((N = FindNodeOrInsertPos(ID, DL, IP)))
if (!VT.isVector())
return SDValue(N, 0);

if (!N) {
N = newSDNode<ConstantFPSDNode>(isTarget, &V, VTs);
N = newSDNode<ConstantFPSDNode>(isTarget, Elt, VTs);
CSEMap.InsertNode(N, IP);
InsertNode(N);
}
Expand Down
1 change: 1 addition & 0 deletions llvm/test/CodeGen/AArch64/sve-fp-immediates-merging.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,5 +1,6 @@
; NOTE: Assertions have been autogenerated by utils/update_llc_test_checks.py
; RUN: llc < %s | FileCheck %s
; RUN: llc -use-constant-fp-for-scalable-splat < %s | FileCheck %s

target triple = "aarch64-unknown-linux-gnu"

Expand Down
1 change: 1 addition & 0 deletions llvm/test/CodeGen/AArch64/sve-int-imm.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,4 +1,5 @@
; RUN: llc -mtriple=aarch64-linux-gnu -mattr=+sve < %s | FileCheck %s
; RUN: llc -mtriple=aarch64-linux-gnu -mattr=+sve -use-constant-int-for-scalable-splat < %s | FileCheck %s

;
; SVE Arith Vector Immediate Unpredicated CodeGen
Expand Down
Loading