[clang] [CIR] Upstream unary not for ComplexType (PR #148857)

[Henrich Lauko via cfe-commits]

================
@@ -22,15 +24,68 @@ struct LoweringPreparePass : public LoweringPrepareBase<LoweringPreparePass> {
   void runOnOperation() override;
 
   void runOnOp(Operation *op);
+  void lowerUnaryOp(UnaryOp op);
 };
 
 } // namespace
 
-void LoweringPreparePass::runOnOp(Operation *op) {}
+void LoweringPreparePass::lowerUnaryOp(UnaryOp op) {
+  mlir::Type ty = op.getType();
+  if (!mlir::isa<cir::ComplexType>(ty))
+    return;
+
+  mlir::Location loc = op.getLoc();
+  cir::UnaryOpKind opKind = op.getKind();
+
+  CIRBaseBuilderTy builder(getContext());
+  builder.setInsertionPointAfter(op);
+
+  mlir::Value operand = op.getInput();
+  mlir::Value operandReal = builder.createComplexReal(loc, operand);
+  mlir::Value operandImag = builder.createComplexImag(loc, operand);
+
+  mlir::Value resultReal;
+  mlir::Value resultImag;
+
+  switch (opKind) {
+  case cir::UnaryOpKind::Inc:
+  case cir::UnaryOpKind::Dec:
+    llvm_unreachable("Complex unary Inc/Dec NYI");
+    break;
+
+  case cir::UnaryOpKind::Plus:
+  case cir::UnaryOpKind::Minus:
+    llvm_unreachable("Complex unary Plus/Minus NYI");
+    break;
+
+  case cir::UnaryOpKind::Not:
+    resultReal = operandReal;
+    resultImag =
+        builder.createUnaryOp(loc, cir::UnaryOpKind::Minus, operandImag);
+    break;
+  }
+
+  auto result = builder.createComplexCreate(loc, resultReal, resultImag);
+  op.replaceAllUsesWith(result);
+  op.erase();
+}
+
+void LoweringPreparePass::runOnOp(Operation *op) {
+  if (auto unary = dyn_cast<UnaryOp>(op)) {
+    lowerUnaryOp(unary);
+  }
+}
 
 void LoweringPreparePass::runOnOperation() {
+  mlir::Operation *op = getOperation();
+
   llvm::SmallVector<Operation *> opsToTransform;
 
+  op->walk([&](Operation *op) {
+    if (isa<UnaryOp>(op))
----------------
xlauko wrote:

```suggestion
    if (mlir::isa<cir::UnaryOp>(op))
```

https://github.com/llvm/llvm-project/pull/148857