[mlir][complex] Add complex-range option and select complex division … (llvm#127010)

…algorithm

This patch adds the `complex-range` option and two calculation methods
for complex number division (algebraic method and Smith's algorithm) to
both the `ComplexToLLVM` and `ComplexToStandard` passes, allowing the
calculation method to be controlled by the option.

See also the discussion in the following discourse post.


https://discourse.llvm.org/t/question-and-proposal-regarding-complex-number-division-algorithm-in-the-complex-dialect/83772

Author: s-watanabe314

mlir/include/mlir/Conversion/ComplexCommon/DivisionConverter.h

@@ -0,0 +1,48 @@
+//===- DivisionConverter.h - Complex division conversion ------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef MLIR_CONVERSION_COMPLEXCOMMON_DIVISIONCONVERTER_H
+#define MLIR_CONVERSION_COMPLEXCOMMON_DIVISIONCONVERTER_H
+
+#include "mlir/Conversion/LLVMCommon/ConversionTarget.h"
+#include "mlir/Dialect/Arith/IR/Arith.h"
+#include "mlir/Dialect/LLVMIR/LLVMDialect.h"
+
+namespace mlir {
+namespace complex {
+/// convert a complex division to the LLVM dialect using algebraic method
+void convertDivToLLVMUsingAlgebraic(ConversionPatternRewriter &rewriter,
+                                    Location loc, Value lhsRe, Value lhsIm,
+                                    Value rhsRe, Value rhsIm,
+                                    LLVM::FastmathFlagsAttr fmf,
+                                    Value *resultRe, Value *resultIm);
+
+/// convert a complex division to the arith/math dialects using algebraic method
+void convertDivToStandardUsingAlgebraic(ConversionPatternRewriter &rewriter,
+                                        Location loc, Value lhsRe, Value lhsIm,
+                                        Value rhsRe, Value rhsIm,
+                                        arith::FastMathFlagsAttr fmf,
+                                        Value *resultRe, Value *resultIm);
+
+/// convert a complex division to the LLVM dialect using Smith's method
+void convertDivToLLVMUsingRangeReduction(ConversionPatternRewriter &rewriter,
+                                         Location loc, Value lhsRe, Value lhsIm,
+                                         Value rhsRe, Value rhsIm,
+                                         LLVM::FastmathFlagsAttr fmf,
+                                         Value *resultRe, Value *resultIm);
+
+/// convert a complex division to the arith/math dialects using Smith's method
+void convertDivToStandardUsingRangeReduction(
+    ConversionPatternRewriter &rewriter, Location loc, Value lhsRe, Value lhsIm,
+    Value rhsRe, Value rhsIm, arith::FastMathFlagsAttr fmf, Value *resultRe,
+    Value *resultIm);
+
+} // namespace complex
+} // namespace mlir
+
+#endif // MLIR_CONVERSION_COMPLEXCOMMON_DIVISIONCONVERTER_H

mlir/include/mlir/Conversion/ComplexToLLVM/ComplexToLLVM.h

@@ -9,6 +9,8 @@
 #define MLIR_CONVERSION_COMPLEXTOLLVM_COMPLEXTOLLVM_H_
 
 #include "mlir/Conversion/LLVMCommon/StructBuilder.h"
+#include "mlir/Dialect/Complex/IR/Complex.h"
+#include "mlir/Pass/Pass.h"
 
 namespace mlir {
 class DialectRegistry;
@@ -39,8 +41,10 @@ class ComplexStructBuilder : public StructBuilder {
 };
 
 /// Populate the given list with patterns that convert from Complex to LLVM.
-void populateComplexToLLVMConversionPatterns(const LLVMTypeConverter &converter,
-                                             RewritePatternSet &patterns);
+void populateComplexToLLVMConversionPatterns(
+    const LLVMTypeConverter &converter, RewritePatternSet &patterns,
+    mlir::complex::ComplexRangeFlags complexRange =
+        mlir::complex::ComplexRangeFlags::basic);
 
 void registerConvertComplexToLLVMInterface(DialectRegistry &registry);
 

mlir/include/mlir/Conversion/ComplexToStandard/ComplexToStandard.h

@@ -8,6 +8,8 @@
 #ifndef MLIR_CONVERSION_COMPLEXTOSTANDARD_COMPLEXTOSTANDARD_H_
 #define MLIR_CONVERSION_COMPLEXTOSTANDARD_COMPLEXTOSTANDARD_H_
 
+#include "mlir/Dialect/Complex/IR/Complex.h"
+#include "mlir/Pass/Pass.h"
 #include <memory>
 
 namespace mlir {
@@ -18,10 +20,15 @@ class Pass;
 #include "mlir/Conversion/Passes.h.inc"
 
 /// Populate the given list with patterns that convert from Complex to Standard.
-void populateComplexToStandardConversionPatterns(RewritePatternSet &patterns);
+void populateComplexToStandardConversionPatterns(
+    RewritePatternSet &patterns,
+    mlir::complex::ComplexRangeFlags complexRange =
+        mlir::complex::ComplexRangeFlags::improved);
 
 /// Create a pass to convert Complex operations to the Standard dialect.
 std::unique_ptr<Pass> createConvertComplexToStandardPass();
+std::unique_ptr<Pass>
+createConvertComplexToStandardPass(ConvertComplexToStandardOptions options);
 
 } // namespace mlir
 

mlir/include/mlir/Conversion/Passes.td

@@ -274,6 +274,17 @@ def ConvertBufferizationToMemRef : Pass<"convert-bufferization-to-memref"> {
 def ConvertComplexToLLVMPass : Pass<"convert-complex-to-llvm"> {
   let summary = "Convert Complex dialect to LLVM dialect";
   let dependentDialects = ["LLVM::LLVMDialect"];
+
+  let options = [
+    Option<"complexRange", "complex-range", "::mlir::complex::ComplexRangeFlags",
+      /*default=*/"::mlir::complex::ComplexRangeFlags::basic",
+      "Control the intermediate calculation of complex number division",
+      [{::llvm::cl::values(
+        clEnumValN(::mlir::complex::ComplexRangeFlags::improved, "improved", "improved"),
+        clEnumValN(::mlir::complex::ComplexRangeFlags::basic, "basic", "basic (default)"),
+        clEnumValN(::mlir::complex::ComplexRangeFlags::none, "none", "none")
+      )}]>,
+  ];
 }
 
 //===----------------------------------------------------------------------===//
@@ -308,6 +319,17 @@ def ConvertComplexToStandard : Pass<"convert-complex-to-standard"> {
   let summary = "Convert Complex dialect to standard dialect";
   let constructor = "mlir::createConvertComplexToStandardPass()";
   let dependentDialects = ["math::MathDialect"];
+
+  let options = [
+    Option<"complexRange", "complex-range", "::mlir::complex::ComplexRangeFlags",
+      /*default=*/"::mlir::complex::ComplexRangeFlags::improved",
+      "Control the intermediate calculation of complex number division",
+      [{::llvm::cl::values(
+        clEnumValN(::mlir::complex::ComplexRangeFlags::improved, "improved", "improved (default)"),
+        clEnumValN(::mlir::complex::ComplexRangeFlags::basic, "basic", "basic"),
+        clEnumValN(::mlir::complex::ComplexRangeFlags::none, "none", "none")
+      )}]>,
+  ];
 }
 
 //===----------------------------------------------------------------------===//

mlir/include/mlir/Dialect/Complex/IR/CMakeLists.txt

@@ -2,6 +2,8 @@ add_mlir_dialect(ComplexOps complex)
 add_mlir_doc(ComplexOps ComplexOps Dialects/ -gen-dialect-doc  -dialect=complex)
 
 set(LLVM_TARGET_DEFINITIONS ComplexAttributes.td)
+mlir_tablegen(ComplexEnums.h.inc -gen-enum-decls)
+mlir_tablegen(ComplexEnums.cpp.inc -gen-enum-defs)
 mlir_tablegen(ComplexAttributes.h.inc -gen-attrdef-decls)
 mlir_tablegen(ComplexAttributes.cpp.inc -gen-attrdef-defs)
 add_public_tablegen_target(MLIRComplexAttributesIncGen)

mlir/include/mlir/Dialect/Complex/IR/Complex.h

@@ -22,6 +22,12 @@
 
 #include "mlir/Dialect/Complex/IR/ComplexOpsDialect.h.inc"
 
+//===----------------------------------------------------------------------===//
+// Complex Dialect Enums
+//===----------------------------------------------------------------------===//
+
+#include "mlir/Dialect/Complex/IR/ComplexEnums.h.inc"
+
 //===----------------------------------------------------------------------===//
 // Complex Dialect Operations
 //===----------------------------------------------------------------------===//

mlir/include/mlir/Dialect/Complex/IR/ComplexBase.td

@@ -9,6 +9,7 @@
 #ifndef COMPLEX_BASE
 #define COMPLEX_BASE
 
+include "mlir/IR/EnumAttr.td"
 include "mlir/IR/OpBase.td"
 
 def Complex_Dialect : Dialect {
@@ -24,4 +25,19 @@ def Complex_Dialect : Dialect {
   let useDefaultAttributePrinterParser = 1;
 }
 
+//===----------------------------------------------------------------------===//
+// Complex_ComplexRangeFlags
+//===----------------------------------------------------------------------===//
+
+def Complex_CRF_improved  : I32BitEnumAttrCaseBit<"improved", 0>;
+def Complex_CRF_basic : I32BitEnumAttrCaseBit<"basic", 1>;
+def Complex_CRF_none  : I32BitEnumAttrCaseBit<"none", 2>;
+
+def Complex_ComplexRangeFlags : I32BitEnumAttr<
+    "ComplexRangeFlags",
+    "Complex range flags",
+    [Complex_CRF_improved, Complex_CRF_basic, Complex_CRF_none]> {
+  let cppNamespace = "::mlir::complex";
+}
+
 #endif // COMPLEX_BASE

mlir/lib/Conversion/CMakeLists.txt

@@ -11,6 +11,7 @@ add_subdirectory(ArmSMEToSCF)
 add_subdirectory(ArmSMEToLLVM)
 add_subdirectory(AsyncToLLVM)
 add_subdirectory(BufferizationToMemRef)
+add_subdirectory(ComplexCommon)
 add_subdirectory(ComplexToLibm)
 add_subdirectory(ComplexToLLVM)
 add_subdirectory(ComplexToSPIRV)

mlir/lib/Conversion/ComplexCommon/CMakeLists.txt

@@ -0,0 +1,12 @@
+add_mlir_conversion_library(MLIRComplexDivisionConversion
+  DivisionConverter.cpp
+
+  LINK_COMPONENTS
+  Core
+
+  LINK_LIBS PUBLIC
+  MLIRArithDialect
+  MLIRComplexDialect
+  MLIRLLVMDialect
+  MLIRMathDialect
+  )