Skip to content
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

[CIR][Lowering][NFC] Refactor LoopOp lowering #406

Merged
merged 5 commits into from
Jan 22, 2024
Merged

[CIR][Lowering][NFC] Refactor LoopOp lowering #406

Changes from all commits
Commits
Show all changes
5 commits
Select commit Hold shift + click to select a range
7e4951f
[CIR][Lowering][NFC] Refactor LoopOp lowering
sitio-couto Jan 18, 2024
4643158
Update on "[CIR][Lowering][NFC] Refactor LoopOp lowering"
sitio-couto Jan 18, 2024
8d78c33
Update on "[CIR][Lowering][NFC] Refactor LoopOp lowering"
sitio-couto Jan 20, 2024
242e3bf
Update on "[CIR][Lowering][NFC] Refactor LoopOp lowering"
sitio-couto Jan 20, 2024
fd36118
Update on "[CIR][Lowering][NFC] Refactor LoopOp lowering"
sitio-couto Jan 22, 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
106 changes: 45 additions & 61 deletions clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -405,10 +405,11 @@ class CIRPtrStrideOpLowering
}
};

class CIRLoopOpLowering : public mlir::OpConversionPattern<mlir::cir::LoopOp> {
class CIRLoopOpInterfaceLowering
: public mlir::OpInterfaceConversionPattern<mlir::cir::LoopOpInterface> {
public:
using mlir::OpConversionPattern<mlir::cir::LoopOp>::OpConversionPattern;
using LoopKind = mlir::cir::LoopOpKind;
using mlir::OpInterfaceConversionPattern<
mlir::cir::LoopOpInterface>::OpInterfaceConversionPattern;

inline void
lowerConditionOp(mlir::cir::ConditionOp op, mlir::Block *body,
Expand All @@ -421,76 +422,59 @@ class CIRLoopOpLowering : public mlir::OpConversionPattern<mlir::cir::LoopOp> {
}

mlir::LogicalResult
matchAndRewrite(mlir::cir::LoopOp loopOp, OpAdaptor adaptor,
mlir::ConversionPatternRewriter &rewriter) const override {
auto kind = loopOp.getKind();
auto *currentBlock = rewriter.getInsertionBlock();
auto *continueBlock =
rewriter.splitBlock(currentBlock, rewriter.getInsertionPoint());
matchAndRewrite(mlir::cir::LoopOpInterface op,
mlir::ArrayRef<mlir::Value> operands,
mlir::ConversionPatternRewriter &rewriter) const final {
// Setup CFG blocks.
auto *entry = rewriter.getInsertionBlock();
auto *exit = rewriter.splitBlock(entry, rewriter.getInsertionPoint());
auto *cond = &op.getCond().front();
auto *body = &op.getBody().front();
auto *step = (op.maybeGetStep() ? &op.maybeGetStep()->front() : nullptr);

// Setup loop entry branch.
rewriter.setInsertionPointToEnd(entry);
rewriter.create<mlir::LLVM::BrOp>(op.getLoc(), &op.getEntry().front());

// Fetch required info from the condition region.
auto &condRegion = loopOp.getCond();
auto &condFrontBlock = condRegion.front();

// Fetch required info from the body region.
auto &bodyRegion = loopOp.getBody();
auto &bodyFrontBlock = bodyRegion.front();
auto bodyYield =
dyn_cast<mlir::cir::YieldOp>(bodyRegion.back().getTerminator());
// Branch from condition region to body or exit.
auto conditionOp = cast<mlir::cir::ConditionOp>(cond->getTerminator());
lowerConditionOp(conditionOp, body, exit, rewriter);

// Fetch required info from the step region.
auto &stepRegion = loopOp.getStep();
auto &stepFrontBlock = stepRegion.front();
auto stepYield =
dyn_cast<mlir::cir::YieldOp>(stepRegion.back().getTerminator());
auto &stepBlock = (kind == LoopKind::For ? stepFrontBlock : condFrontBlock);
// TODO(cir): Remove the walks below. It visits operations unnecessarily,
// however, to solve this we would likely need a custom DialecConversion
// driver to customize the order that operations are visited.

// Lower continue statements.
mlir::Block &dest =
(kind != LoopKind::For ? condFrontBlock : stepFrontBlock);
walkRegionSkipping<mlir::cir::LoopOpInterface>(
loopOp.getBody(), [&](mlir::Operation *op) {
if (isa<mlir::cir::ContinueOp>(op))
lowerTerminator(op, &dest, rewriter);
});
mlir::Block *dest = (step ? step : cond);
op.walkBodySkippingNestedLoops([&](mlir::Operation *op) {
if (isa<mlir::cir::ContinueOp>(op))
lowerTerminator(op, dest, rewriter);
});

// Lower break statements.
walkRegionSkipping<mlir::cir::LoopOpInterface, mlir::cir::SwitchOp>(
loopOp.getBody(), [&](mlir::Operation *op) {
op.getBody(), [&](mlir::Operation *op) {
if (isa<mlir::cir::BreakOp>(op))
lowerTerminator(op, continueBlock, rewriter);
lowerTerminator(op, exit, rewriter);
});

// Move loop op region contents to current CFG.
rewriter.inlineRegionBefore(condRegion, continueBlock);
rewriter.inlineRegionBefore(bodyRegion, continueBlock);
if (kind == LoopKind::For) // Ignore step if not a for-loop.
rewriter.inlineRegionBefore(stepRegion, continueBlock);
// Lower optional body region yield.
auto bodyYield = dyn_cast<mlir::cir::YieldOp>(body->getTerminator());
if (bodyYield)
lowerTerminator(bodyYield, (step ? step : cond), rewriter);

// Set loop entry point to condition or to body in do-while cases.
rewriter.setInsertionPointToEnd(currentBlock);
auto &entry = (kind != LoopKind::DoWhile ? condFrontBlock : bodyFrontBlock);
rewriter.create<mlir::cir::BrOp>(loopOp.getLoc(), &entry);

// Branch from condition region to body or exit.
auto conditionOp =
cast<mlir::cir::ConditionOp>(condFrontBlock.getTerminator());
lowerConditionOp(conditionOp, &bodyFrontBlock, continueBlock, rewriter);

// Branch from body to condition or to step on for-loop cases.
if (bodyYield) {
rewriter.setInsertionPoint(bodyYield);
rewriter.replaceOpWithNewOp<mlir::cir::BrOp>(bodyYield, &stepBlock);
}
// Lower mandatory step region yield.
if (step)
lowerTerminator(cast<mlir::cir::YieldOp>(step->getTerminator()), cond,
rewriter);

// Is a for loop: branch from step to condition.
if (kind == LoopKind::For) {
rewriter.setInsertionPoint(stepYield);
rewriter.replaceOpWithNewOp<mlir::cir::BrOp>(stepYield, &condFrontBlock);
}
// Move region contents out of the loop op.
rewriter.inlineRegionBefore(op.getCond(), exit);
rewriter.inlineRegionBefore(op.getBody(), exit);
if (step)
rewriter.inlineRegionBefore(*op.maybeGetStep(), exit);

// Remove the loop op.
rewriter.eraseOp(loopOp);
rewriter.eraseOp(op);
return mlir::success();
}
};
Expand Down Expand Up @@ -2097,7 +2081,7 @@ void populateCIRToLLVMConversionPatterns(mlir::RewritePatternSet &patterns,
mlir::TypeConverter &converter) {
patterns.add<CIRReturnLowering>(patterns.getContext());
patterns.add<
CIRCmpOpLowering, CIRLoopOpLowering, CIRBrCondOpLowering,
CIRCmpOpLowering, CIRLoopOpInterfaceLowering, CIRBrCondOpLowering,
CIRPtrStrideOpLowering, CIRCallLowering, CIRUnaryOpLowering,
CIRBinOpLowering, CIRShiftOpLowering, CIRLoadLowering,
CIRConstantLowering, CIRStoreLowering, CIRAllocaLowering, CIRFuncLowering,
Expand Down