[CIR][CodeGen] Basic lowering of increment/decrement

Author: cmarcelo

clang/lib/CIR/CodeGen/LowerToLLVM.cpp

@@ -207,6 +207,37 @@ class CIRFuncLowering : public mlir::OpRewritePattern<mlir::cir::FuncOp> {
   }
 };
 
+class CIRUnaryOpLowering : public mlir::OpRewritePattern<mlir::cir::UnaryOp> {
+public:
+  using OpRewritePattern<mlir::cir::UnaryOp>::OpRewritePattern;
+
+  mlir::LogicalResult
+  matchAndRewrite(mlir::cir::UnaryOp op,
+                  mlir::PatternRewriter &rewriter) const override {
+    mlir::Type type = op.getInput().getType();
+    assert(type.isa<mlir::IntegerType>() && "operand type not supported yet");
+
+    switch (op.getKind()) {
+    case mlir::cir::UnaryOpKind::Inc: {
+      auto One = rewriter.create<mlir::arith::ConstantOp>(
+          op.getLoc(), type, mlir::IntegerAttr::get(type, 1));
+      rewriter.replaceOpWithNewOp<mlir::arith::AddIOp>(op, op.getType(),
+                                                       op.getInput(), One);
+      break;
+    }
+    case mlir::cir::UnaryOpKind::Dec: {
+      auto One = rewriter.create<mlir::arith::ConstantOp>(
+          op.getLoc(), type, mlir::IntegerAttr::get(type, 1));
+      rewriter.replaceOpWithNewOp<mlir::arith::SubIOp>(op, op.getType(),
+                                                       op.getInput(), One);
+      break;
+    }
+    }
+
+    return mlir::LogicalResult::success();
+  }
+};
+
 class CIRBinOpLowering : public mlir::OpRewritePattern<mlir::cir::BinOp> {
 public:
   using OpRewritePattern<mlir::cir::BinOp>::OpRewritePattern;
@@ -448,8 +479,8 @@ class CIRBrOpLowering : public mlir::OpRewritePattern<mlir::cir::BrOp> {
 
 void populateCIRToMemRefConversionPatterns(mlir::RewritePatternSet &patterns) {
   patterns.add<CIRAllocaLowering, CIRLoadLowering, CIRStoreLowering,
-               CIRConstantLowering, CIRBinOpLowering, CIRCmpOpLowering,
-               CIRBrOpLowering>(patterns.getContext());
+               CIRConstantLowering, CIRUnaryOpLowering, CIRBinOpLowering,
+               CIRCmpOpLowering, CIRBrOpLowering>(patterns.getContext());
 }
 
 void ConvertCIRToLLVMPass::runOnOperation() {

clang/test/CIR/CIRToLLVM/unary-inc-dec.cir

@@ -0,0 +1,29 @@
+// RUN: cir-tool %s -cir-to-func -cir-to-memref -o - | FileCheck %s -check-prefix=MLIR
+// RUN: cir-tool %s -cir-to-func -cir-to-memref -cir-to-llvm -o - | mlir-translate -mlir-to-llvmir | FileCheck %s -check-prefix=LLVM
+
+module {
+  cir.func @foo() {
+    %0 = cir.alloca i32, cir.ptr <i32>, ["a", cinit] {alignment = 4 : i64}
+    %1 = cir.alloca i32, cir.ptr <i32>, ["b", cinit] {alignment = 4 : i64}
+    %2 = cir.cst(2 : i32) : i32
+    cir.store %2, %0 : i32, cir.ptr <i32>
+    cir.store %2, %1 : i32, cir.ptr <i32>
+    
+    %3 = cir.load %0 : cir.ptr <i32>, i32
+    %4 = cir.unary(inc, %3) : i32, i32
+    cir.store %4, %0 : i32, cir.ptr <i32>
+
+    %5 = cir.load %1 : cir.ptr <i32>, i32
+    %6 = cir.unary(dec, %5) : i32, i32
+    cir.store %6, %1 : i32, cir.ptr <i32>
+    cir.return
+  }
+}
+
+// MLIR: = arith.constant 1
+// MLIR: = arith.addi
+// MLIR: = arith.constant 1
+// MLIR: = arith.subi
+
+// LLVM: = add i32 %[[#]], 1
+// LLVM: = sub i32 %[[#]], 1