[CIR] Add bit reverse and byte reverse operations

Lancern · Lancern · commit 35ca85872ebc · 2025-07-07T00:45:48.000+08:00
diff --git a/clang/include/clang/CIR/Dialect/IR/CIROps.td b/clang/include/clang/CIR/Dialect/IR/CIROps.td
@@ -2661,6 +2661,55 @@ def BitPopcountOp : CIR_BitOpBase<"bit.popcnt",
   }];
 }
 
+def BitReverseOp : CIR_BitOpBase<"bit.reverse", CIR_UIntOfWidths<[8, 16, 32, 64]>> {
+  let summary = "Reverse the bit pattern of the operand integer";
+  let description = [{
+    The `cir.bit.reverse` operation reverses the bits of the operand integer.
+    Its only argument must be of unsigned integer types of width 8, 16, 32, or
+    64.
+
+    This operation covers the C/C++ builtin function `__builtin_bitreverse`.
+
+    Example:
+
+    ```mlir
+    %1 = cir.bit.reverse %0 : !u32i
+    ```
+  }];
+}
+
+//===----------------------------------------------------------------------===//
+// ByteswapOp
+//===----------------------------------------------------------------------===//
+
+def ByteSwapOp : CIR_Op<"bswap", [Pure, SameOperandsAndResultType]> {
+  let summary = "Reverse the bytes in the object representation of the operand";
+  let description = [{
+    The `cir.bswap` operation takes an integer as operand, reverse the bytes in
+    the object representation of the operand integer, and returns the result.
+
+    The operand integer must be an unsigned integer. Its widths must be either
+    16, 32, or 64.
+
+    Example:
+
+    ```mlir
+    // %0 = 0x12345678
+    %0 = cir.const #cir.int<305419896> : !u32i
+
+    // %1 should be 0x78563412
+    %1 = cir.bswap(%0 : !u32i) : !u32i
+    ```
+  }];
+
+  let results = (outs CIR_IntType:$result);
+  let arguments = (ins CIR_UIntOfWidths<[16, 32, 64]>:$input);
+
+  let assemblyFormat = [{
+    `(` $input `:` type($input) `)` `:` type($result) attr-dict
+  }];
+}
+
 //===----------------------------------------------------------------------===//
 // Assume Operations
 //===----------------------------------------------------------------------===//
diff --git a/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp b/clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp
@@ -190,6 +190,26 @@ RValue CIRGenFunction::emitBuiltinExpr(const GlobalDecl &gd, unsigned builtinID,
                                                 expectedValue, probAttr);
     return RValue::get(result);
   }
+
+  case Builtin::BI__builtin_bswap16:
+  case Builtin::BI__builtin_bswap32:
+  case Builtin::BI__builtin_bswap64:
+  case Builtin::BI_byteswap_ushort:
+  case Builtin::BI_byteswap_ulong:
+  case Builtin::BI_byteswap_uint64: {
+    mlir::Value arg = emitScalarExpr(e->getArg(0));
+    return RValue::get(
+        builder.create<cir::ByteSwapOp>(getLoc(e->getSourceRange()), arg));
+  }
+
+  case Builtin::BI__builtin_bitreverse8:
+  case Builtin::BI__builtin_bitreverse16:
+  case Builtin::BI__builtin_bitreverse32:
+  case Builtin::BI__builtin_bitreverse64: {
+    mlir::Value arg = emitScalarExpr(e->getArg(0));
+    return RValue::get(
+        builder.create<cir::BitReverseOp>(getLoc(e->getSourceRange()), arg));
+  }
   }
 
   cgm.errorNYI(e->getSourceRange(), "unimplemented builtin call");
diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp
@@ -535,6 +535,13 @@ mlir::LogicalResult CIRToLLVMBitPopcountOpLowering::matchAndRewrite(
   return mlir::LogicalResult::success();
 }
 
+mlir::LogicalResult CIRToLLVMBitReverseOpLowering::matchAndRewrite(
+    cir::BitReverseOp op, OpAdaptor adaptor,
+    mlir::ConversionPatternRewriter &rewriter) const {
+  rewriter.replaceOpWithNewOp<mlir::LLVM::BitReverseOp>(op, adaptor.getInput());
+  return mlir::success();
+}
+
 mlir::LogicalResult CIRToLLVMBrCondOpLowering::matchAndRewrite(
     cir::BrCondOp brOp, OpAdaptor adaptor,
     mlir::ConversionPatternRewriter &rewriter) const {
@@ -551,6 +558,13 @@ mlir::LogicalResult CIRToLLVMBrCondOpLowering::matchAndRewrite(
   return mlir::success();
 }
 
+mlir::LogicalResult CIRToLLVMByteSwapOpLowering::matchAndRewrite(
+    cir::ByteSwapOp op, OpAdaptor adaptor,
+    mlir::ConversionPatternRewriter &rewriter) const {
+  rewriter.replaceOpWithNewOp<mlir::LLVM::ByteSwapOp>(op, adaptor.getInput());
+  return mlir::LogicalResult::success();
+}
+
 mlir::Type CIRToLLVMCastOpLowering::convertTy(mlir::Type ty) const {
   return getTypeConverter()->convertType(ty);
 }
@@ -2035,8 +2049,10 @@ void ConvertCIRToLLVMPass::runOnOperation() {
                CIRToLLVMBitCtzOpLowering,
                CIRToLLVMBitParityOpLowering,
                CIRToLLVMBitPopcountOpLowering,
+               CIRToLLVMBitReverseOpLowering,
                CIRToLLVMBrCondOpLowering,
                CIRToLLVMBrOpLowering,
+               CIRToLLVMByteSwapOpLowering,
                CIRToLLVMCallOpLowering,
                CIRToLLVMCmpOpLowering,
                CIRToLLVMComplexCreateOpLowering,
diff --git a/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h b/clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h
@@ -94,6 +94,16 @@ class CIRToLLVMBitPopcountOpLowering
                   mlir::ConversionPatternRewriter &) const override;
 };
 
+class CIRToLLVMBitReverseOpLowering
+    : public mlir::OpConversionPattern<cir::BitReverseOp> {
+public:
+  using mlir::OpConversionPattern<cir::BitReverseOp>::OpConversionPattern;
+
+  mlir::LogicalResult
+  matchAndRewrite(cir::BitReverseOp op, OpAdaptor,
+                  mlir::ConversionPatternRewriter &) const override;
+};
+
 class CIRToLLVMBrCondOpLowering
     : public mlir::OpConversionPattern<cir::BrCondOp> {
 public:
@@ -104,6 +114,16 @@ class CIRToLLVMBrCondOpLowering
                   mlir::ConversionPatternRewriter &) const override;
 };
 
+class CIRToLLVMByteSwapOpLowering
+    : public mlir::OpConversionPattern<cir::ByteSwapOp> {
+public:
+  using mlir::OpConversionPattern<cir::ByteSwapOp>::OpConversionPattern;
+
+  mlir::LogicalResult
+  matchAndRewrite(cir::ByteSwapOp op, OpAdaptor,
+                  mlir::ConversionPatternRewriter &) const override;
+};
+
 class CIRToLLVMCastOpLowering : public mlir::OpConversionPattern<cir::CastOp> {
   mlir::DataLayout const &dataLayout;
 
diff --git a/clang/test/CIR/CodeGen/builtin_bit.cpp b/clang/test/CIR/CodeGen/builtin_bit.cpp
@@ -325,3 +325,94 @@ int test_builtin_popcountg(unsigned x) {
 
 // OGCG-LABEL: _Z22test_builtin_popcountgj
 // OGCG:         %{{.+}} = call i32 @llvm.ctpop.i32(i32 %{{.+}})
+
+unsigned char test_builtin_bitreverse8(unsigned char x) {
+  return __builtin_bitreverse8(x);
+}
+
+// CIR-LABEL: @_Z24test_builtin_bitreverse8h
+// CIR:         %{{.+}} = cir.bit.reverse(%{{.+}} : !u8i) : !u8i
+
+// LLVM-LABEL: @_Z24test_builtin_bitreverse8h
+// LLVM:         %{{.+}} = call i8 @llvm.bitreverse.i8(i8 %{{.+}})
+
+// OGCG-LABEL: @_Z24test_builtin_bitreverse8h
+// OGCG:         %{{.+}} = call i8 @llvm.bitreverse.i8(i8 %{{.+}})
+
+unsigned short test_builtin_bitreverse16(unsigned short x) {
+  return __builtin_bitreverse16(x);
+}
+
+// CIR-LABEL: @_Z25test_builtin_bitreverse16t
+// CIR:         %{{.+}} = cir.bit.reverse(%{{.+}} : !u16i) : !u16i
+
+// LLVM-LABEL: @_Z25test_builtin_bitreverse16t
+// LLVM:         %{{.+}} = call i16 @llvm.bitreverse.i16(i16 %{{.+}})
+
+// OGCG-LABEL: @_Z25test_builtin_bitreverse16t
+// OGCG:         %{{.+}} = call i16 @llvm.bitreverse.i16(i16 %{{.+}})
+
+unsigned test_builtin_bitreverse32(unsigned x) {
+  return __builtin_bitreverse32(x);
+}
+
+// CIR-LABEL: @_Z25test_builtin_bitreverse32j
+// CIR:         %{{.+}} = cir.bit.reverse(%{{.+}} : !u32i) : !u32i
+
+// LLVM-LABEL: @_Z25test_builtin_bitreverse32j
+// LLVM:         %{{.+}} = call i32 @llvm.bitreverse.i32(i32 %{{.+}})
+
+// OGCG-LABEL: @_Z25test_builtin_bitreverse32j
+// OGCG:         %{{.+}} = call i32 @llvm.bitreverse.i32(i32 %{{.+}})
+
+unsigned long long test_builtin_bitreverse64(unsigned long long x) {
+  return __builtin_bitreverse64(x);
+}
+
+// CIR-LABEL: @_Z25test_builtin_bitreverse64y
+// CIR:         %{{.+}} = cir.bit.reverse(%{{.+}} : !u64i) : !u64i
+
+// LLVM-LABEL: @_Z25test_builtin_bitreverse64y
+// LLVM:         %{{.+}} = call i64 @llvm.bitreverse.i64(i64 %{{.+}})
+
+// OGCG-LABEL: @_Z25test_builtin_bitreverse64y
+// OGCG:         %{{.+}} = call i64 @llvm.bitreverse.i64(i64 %{{.+}})
+
+unsigned short test_builtin_bswap16(unsigned short x) {
+  return __builtin_bswap16(x);
+}
+
+// CIR-LABEL: @_Z20test_builtin_bswap16t
+// CIR:         %{{.+}} = cir.bswap(%{{.+}} : !u16i) : !u16i
+
+// LLVM-LABEL: @_Z20test_builtin_bswap16t
+// LLVM:         %{{.+}} = call i16 @llvm.bswap.i16(i16 %{{.+}})
+
+// OGCG-LABEL: @_Z20test_builtin_bswap16t
+// OGCG:         %{{.+}} = call i16 @llvm.bswap.i16(i16 %{{.+}})
+
+unsigned test_builtin_bswap32(unsigned x) {
+  return __builtin_bswap32(x);
+}
+
+// CIR-LABEL: @_Z20test_builtin_bswap32j
+// CIR:         %{{.+}} = cir.bswap(%{{.+}} : !u32i) : !u32i
+
+// LLVM-LABEL: @_Z20test_builtin_bswap32j
+// LLVM:         %{{.+}} = call i32 @llvm.bswap.i32(i32 %{{.+}})
+
+// OGCG-LABEL: @_Z20test_builtin_bswap32j
+// OGCG:         %{{.+}} = call i32 @llvm.bswap.i32(i32 %{{.+}})
+
+unsigned long long test_builtin_bswap64(unsigned long long x) {
+  return __builtin_bswap64(x);
+}
+
+// CIR-LABEL: @_Z20test_builtin_bswap64y
+// CIR:         %{{.+}} = cir.bswap(%{{.+}} : !u64i) : !u64i
+
+// LLVM-LABEL: @_Z20test_builtin_bswap64y
+// LLVM:         %{{.+}} = call i64 @llvm.bswap.i64(i64 %{{.+}})
+
+// OGCG-LABEL: @_Z20test_builtin_bswap64y
+// OGCG:         %{{.+}} = call i64 @llvm.bswap.i64(i64 %{{.+}})
