Skip to content

[HLSL] Move FNeg legalization to the DXILLegalization pass #140942

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 4 commits into from
May 22, 2025
Merged

[HLSL] Move FNeg legalization to the DXILLegalization pass #140942

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
4 commits
Select commit Hold shift + click to select a range
a3fb01d
Move fneg to fsub to DXILLegalizePass
sumitsays May 21, 2025
50ed443
Merge branch 'fork/main' into user/sumita/legalizeFneg
sumitsays May 21, 2025
1571c54
Addressed PR nit comments
sumitsays May 21, 2025
968e0ed
clang format
sumitsays May 21, 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
15 changes: 15 additions & 0 deletions llvm/lib/Target/DirectX/DXILLegalizePass.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -405,6 +405,20 @@ static void removeMemSet(Instruction &I,
ToRemove.push_back(CI);
}

static void updateFnegToFsub(Instruction &I,
SmallVectorImpl<Instruction *> &ToRemove,
DenseMap<Value *, Value *> &) {
const Intrinsic::ID ID = I.getOpcode();
if (ID != Instruction::FNeg)
return;

IRBuilder<> Builder(&I);
Value *In = I.getOperand(0);
Value *Zero = ConstantFP::get(In->getType(), -0.0);
I.replaceAllUsesWith(Builder.CreateFSub(Zero, In));
ToRemove.push_back(&I);
}

namespace {
class DXILLegalizationPipeline {

Expand Down Expand Up @@ -438,6 +452,7 @@ class DXILLegalizationPipeline {
LegalizationPipeline.push_back(legalizeFreeze);
LegalizationPipeline.push_back(legalizeMemCpy);
LegalizationPipeline.push_back(removeMemSet);
LegalizationPipeline.push_back(updateFnegToFsub);
}
};

Expand Down
9 changes: 0 additions & 9 deletions llvm/lib/Target/DirectX/DXILPrepare.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -204,15 +204,6 @@ class DXILPrepareModule : public ModulePass {

I.dropUnknownNonDebugMetadata(DXILCompatibleMDs);

if (I.getOpcode() == Instruction::FNeg) {
Builder.SetInsertPoint(&I);
Value *In = I.getOperand(0);
Value *Zero = ConstantFP::get(In->getType(), -0.0);
I.replaceAllUsesWith(Builder.CreateFSub(Zero, In));
I.eraseFromParent();
continue;
}

// Emtting NoOp bitcast instructions allows the ValueEnumerator to be
// unmodified as it reserves instruction IDs during contruction.
if (auto LI = dyn_cast<LoadInst>(&I)) {
Expand Down
16 changes: 0 additions & 16 deletions llvm/test/CodeGen/DirectX/fneg-conversion.ll
View file
Open in desktop

This file was deleted.

23 changes: 23 additions & 0 deletions llvm/test/CodeGen/DirectX/legalize-fneg.ll
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -0,0 +1,23 @@
; RUN: opt -S -passes='dxil-legalize' -mtriple=dxil-pc-shadermodel6.3-library %s | FileCheck %s

define float @negateF(float %x) {
; CHECK-LABEL: define float @negateF(
; CHECK-SAME: float [[X:%.*]]) {
; CHECK-NEXT: [[ENTRY:.*:]]
; CHECK-NEXT: [[Y:%.*]] = fsub float -0.000000e+00, [[X]]
; CHECK-NEXT: ret float [[Y]]
entry:
%y = fneg float %x
ret float %y
}

define double @negateD(double %x) {
; CHECK-LABEL: define double @negateD(
; CHECK-SAME: double [[X:%.*]]) {
; CHECK-NEXT: [[ENTRY:.*:]]
; CHECK-NEXT: [[Y:%.*]] = fsub double -0.000000e+00, [[X]]
; CHECK-NEXT: ret double [[Y]]
entry:
%y = fneg double %x
ret double %y
}
Loading