llvm-project/mlir/lib/Conversion/ComplexToROCDLLibraryCalls/ComplexToROCDLLibraryCalls.cpp
Akash Banerjee d69ccded4f
[MLIR] Add cpow support in ComplexToROCDLLibraryCalls (#153183)
This PR adds support for complex power operations (`cpow`) in the
`ComplexToROCDLLibraryCalls` conversion pass, specifically targeting
AMDGPU architectures. The implementation optimises complex
exponentiation by using mathematical identities and special-case
handling for small integer powers.

- Force lowering to `complex.pow` operations for the `amdgcn-amd-amdhsa`
target instead of using library calls
- Convert `complex.pow(z, w)` to `complex.exp(w * complex.log(z))` using
mathematical identity
2025-08-20 17:18:30 +00:00

136 lines
5.8 KiB
C++

//=== ComplexToROCDLLibraryCalls.cpp - convert from Complex to ROCDL calls ===//
//
// 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
//
//===----------------------------------------------------------------------===//
#include "mlir/Conversion/ComplexToROCDLLibraryCalls/ComplexToROCDLLibraryCalls.h"
#include "mlir/Dialect/Complex/IR/Complex.h"
#include "mlir/Dialect/Func/IR/FuncOps.h"
#include "mlir/IR/PatternMatch.h"
#include "mlir/Transforms/DialectConversion.h"
namespace mlir {
#define GEN_PASS_DEF_CONVERTCOMPLEXTOROCDLLIBRARYCALLS
#include "mlir/Conversion/Passes.h.inc"
} // namespace mlir
using namespace mlir;
namespace {
template <typename Op, typename FloatTy>
// Pattern to convert Complex ops to ROCDL function calls.
struct ComplexOpToROCDLLibraryCalls : public OpRewritePattern<Op> {
using OpRewritePattern<Op>::OpRewritePattern;
ComplexOpToROCDLLibraryCalls(MLIRContext *context, StringRef funcName,
PatternBenefit benefit = 1)
: OpRewritePattern<Op>(context, benefit), funcName(funcName) {}
LogicalResult matchAndRewrite(Op op, PatternRewriter &rewriter) const final {
Operation *symTable = SymbolTable::getNearestSymbolTable(op);
Type resType = op.getType();
if (auto complexType = dyn_cast<ComplexType>(resType))
resType = complexType.getElementType();
if (!isa<FloatTy>(resType))
return failure();
auto opFunc = dyn_cast_or_null<SymbolOpInterface>(
SymbolTable::lookupSymbolIn(symTable, funcName));
if (!opFunc) {
OpBuilder::InsertionGuard guard(rewriter);
rewriter.setInsertionPointToStart(&symTable->getRegion(0).front());
auto funcTy = FunctionType::get(
rewriter.getContext(), op->getOperandTypes(), op->getResultTypes());
opFunc = func::FuncOp::create(rewriter, rewriter.getUnknownLoc(),
funcName, funcTy);
opFunc.setPrivate();
}
rewriter.replaceOpWithNewOp<func::CallOp>(op, funcName, op.getType(),
op->getOperands());
return success();
}
private:
std::string funcName;
};
// Rewrite complex.pow(z, w) -> complex.exp(w * complex.log(z))
struct PowOpToROCDLLibraryCalls : public OpRewritePattern<complex::PowOp> {
using OpRewritePattern<complex::PowOp>::OpRewritePattern;
LogicalResult matchAndRewrite(complex::PowOp op,
PatternRewriter &rewriter) const final {
Location loc = op.getLoc();
Value logBase = rewriter.create<complex::LogOp>(loc, op.getLhs());
Value mul = rewriter.create<complex::MulOp>(loc, op.getRhs(), logBase);
Value exp = rewriter.create<complex::ExpOp>(loc, mul);
rewriter.replaceOp(op, exp);
return success();
}
};
} // namespace
void mlir::populateComplexToROCDLLibraryCallsConversionPatterns(
RewritePatternSet &patterns) {
patterns.add<PowOpToROCDLLibraryCalls>(patterns.getContext());
patterns.add<ComplexOpToROCDLLibraryCalls<complex::AbsOp, Float32Type>>(
patterns.getContext(), "__ocml_cabs_f32");
patterns.add<ComplexOpToROCDLLibraryCalls<complex::AbsOp, Float64Type>>(
patterns.getContext(), "__ocml_cabs_f64");
patterns.add<ComplexOpToROCDLLibraryCalls<complex::CosOp, Float32Type>>(
patterns.getContext(), "__ocml_ccos_f32");
patterns.add<ComplexOpToROCDLLibraryCalls<complex::CosOp, Float64Type>>(
patterns.getContext(), "__ocml_ccos_f64");
patterns.add<ComplexOpToROCDLLibraryCalls<complex::ExpOp, Float32Type>>(
patterns.getContext(), "__ocml_cexp_f32");
patterns.add<ComplexOpToROCDLLibraryCalls<complex::ExpOp, Float64Type>>(
patterns.getContext(), "__ocml_cexp_f64");
patterns.add<ComplexOpToROCDLLibraryCalls<complex::LogOp, Float32Type>>(
patterns.getContext(), "__ocml_clog_f32");
patterns.add<ComplexOpToROCDLLibraryCalls<complex::LogOp, Float64Type>>(
patterns.getContext(), "__ocml_clog_f64");
patterns.add<ComplexOpToROCDLLibraryCalls<complex::SinOp, Float32Type>>(
patterns.getContext(), "__ocml_csin_f32");
patterns.add<ComplexOpToROCDLLibraryCalls<complex::SinOp, Float64Type>>(
patterns.getContext(), "__ocml_csin_f64");
patterns.add<ComplexOpToROCDLLibraryCalls<complex::SqrtOp, Float32Type>>(
patterns.getContext(), "__ocml_csqrt_f32");
patterns.add<ComplexOpToROCDLLibraryCalls<complex::SqrtOp, Float64Type>>(
patterns.getContext(), "__ocml_csqrt_f64");
patterns.add<ComplexOpToROCDLLibraryCalls<complex::TanOp, Float32Type>>(
patterns.getContext(), "__ocml_ctan_f32");
patterns.add<ComplexOpToROCDLLibraryCalls<complex::TanOp, Float64Type>>(
patterns.getContext(), "__ocml_ctan_f64");
patterns.add<ComplexOpToROCDLLibraryCalls<complex::TanhOp, Float32Type>>(
patterns.getContext(), "__ocml_ctanh_f32");
patterns.add<ComplexOpToROCDLLibraryCalls<complex::TanhOp, Float64Type>>(
patterns.getContext(), "__ocml_ctanh_f64");
}
namespace {
struct ConvertComplexToROCDLLibraryCallsPass
: public impl::ConvertComplexToROCDLLibraryCallsBase<
ConvertComplexToROCDLLibraryCallsPass> {
void runOnOperation() override;
};
} // namespace
void ConvertComplexToROCDLLibraryCallsPass::runOnOperation() {
Operation *op = getOperation();
RewritePatternSet patterns(&getContext());
populateComplexToROCDLLibraryCallsConversionPatterns(patterns);
ConversionTarget target(getContext());
target.addLegalDialect<func::FuncDialect>();
target.addLegalOp<complex::MulOp>();
target.addIllegalOp<complex::AbsOp, complex::CosOp, complex::ExpOp,
complex::LogOp, complex::PowOp, complex::SinOp,
complex::SqrtOp, complex::TanOp, complex::TanhOp>();
if (failed(applyPartialConversion(op, target, std::move(patterns))))
signalPassFailure();
}