[MLIR][ROCDL] Add math.clampf -> rocdl.fmed3 conversion

mlir/include/mlir/Conversion/MathToROCDL/MathToROCDL.h

@@ -9,6 +9,7 @@
 #define MLIR_CONVERSION_MATHTOROCDL_MATHTOROCDL_H_
 
 #include "mlir/Conversion/LLVMCommon/TypeConverter.h"
+#include "mlir/Dialect/AMDGPU/Utils/Chipset.h"
 #include "mlir/IR/PatternMatch.h"
 #include <memory>
 
@@ -20,7 +21,8 @@ class Pass;
 
 /// Populate the given list with patterns that convert from Math to ROCDL calls.
 void populateMathToROCDLConversionPatterns(const LLVMTypeConverter &converter,
-                                           RewritePatternSet &patterns);
+                                           RewritePatternSet &patterns,
+                                           amdgpu::Chipset chipset);
 } // namespace mlir
 
 #endif // MLIR_CONVERSION_MATHTOROCDL_MATHTOROCDL_H_

mlir/include/mlir/Conversion/Passes.td

@@ -785,6 +785,9 @@ def ConvertMathToROCDL : Pass<"convert-math-to-rocdl", "ModuleOp"> {
     "ROCDL::ROCDLDialect",
     "vector::VectorDialect",
   ];
+  let options = [Option<"chipset", "chipset", "std::string",
+                        /*default=*/"\"gfx000\"",
+                        "Chipset that these operations will run on">];
 }
 
 //===----------------------------------------------------------------------===//

mlir/lib/Conversion/GPUToROCDL/LowerGpuOpsToROCDLOps.cpp

@@ -484,5 +484,5 @@ void mlir::populateGpuToROCDLConversionPatterns(
                GPUSubgroupBroadcastOpToROCDL>(converter);
   patterns.add<GPUSubgroupSizeOpToROCDL>(converter, chipset);
 
-  populateMathToROCDLConversionPatterns(converter, patterns);
+  populateMathToROCDLConversionPatterns(converter, patterns, chipset);
 }

mlir/lib/Conversion/MathToROCDL/MathToROCDL.cpp

@@ -10,6 +10,7 @@
 #include "mlir/Conversion/GPUCommon/GPUCommonPass.h"
 #include "mlir/Conversion/LLVMCommon/LoweringOptions.h"
 #include "mlir/Conversion/LLVMCommon/TypeConverter.h"
+#include "mlir/Dialect/AMDGPU/Utils/Chipset.h"
 #include "mlir/Dialect/Func/IR/FuncOps.h"
 #include "mlir/Dialect/LLVMIR/LLVMDialect.h"
 #include "mlir/Dialect/LLVMIR/ROCDLDialect.h"
@@ -42,8 +43,39 @@ static void populateOpPatterns(const LLVMTypeConverter &converter,
                                            f32ApproxFunc, f16Func);
 }
 
+struct ClampFOpConversion final
+    : public ConvertOpToLLVMPattern<math::ClampFOp> {
+  using ConvertOpToLLVMPattern::ConvertOpToLLVMPattern;
+  ClampFOpConversion(const LLVMTypeConverter &converter,
+                     amdgpu::Chipset chipset)
+      : ConvertOpToLLVMPattern<math::ClampFOp>(converter), chipset(chipset) {}
+
+  LogicalResult
+  matchAndRewrite(math::ClampFOp op, OpAdaptor adaptor,
+                  ConversionPatternRewriter &rewriter) const override {
+    // V_MED3_F16/F32 only exists in gfx9+ artchitectures
+    if (chipset.majorVersion < 9) {
+      return rewriter.notifyMatchFailure(
+          op, ("pre-gfx9 (gfx" + std::to_string(chipset.majorVersion) +
+               "): V_MED_F16 / V_MED3_F32 not supported."));
+    }
+    rewriter.replaceOpWithNewOp<ROCDL::FMed3Op>(op, op.getType(), op.getValue(),
+                                                op.getMin(), op.getMax());
+    return success();
+  }
+  amdgpu::Chipset chipset;
+};
+
+static void addChipsetDependentPatterns(const LLVMTypeConverter &converter,
+                                        RewritePatternSet &patterns,
+                                        amdgpu::Chipset chipset) {
+
+  patterns.add<ClampFOpConversion>(converter, chipset);
+}
+
 void mlir::populateMathToROCDLConversionPatterns(
-    const LLVMTypeConverter &converter, RewritePatternSet &patterns) {
+    const LLVMTypeConverter &converter, RewritePatternSet &patterns,
+    amdgpu::Chipset chipset) {
   // Handled by mathToLLVM: math::AbsIOp
   // Handled by mathToLLVM: math::AbsFOp
   // Handled by mathToLLVM: math::CopySignOp
@@ -118,27 +150,31 @@ void mlir::populateMathToROCDLConversionPatterns(
   // worth creating a separate pass for it.
   populateOpPatterns<arith::RemFOp>(converter, patterns, "__ocml_fmod_f32",
                                     "__ocml_fmod_f64", "__ocml_fmod_f16");
+
+  addChipsetDependentPatterns(converter, patterns, chipset);
 }
 
-namespace {
-struct ConvertMathToROCDLPass
-    : public impl::ConvertMathToROCDLBase<ConvertMathToROCDLPass> {
-  ConvertMathToROCDLPass() = default;
+struct ConvertMathToROCDLPass final
+    : impl::ConvertMathToROCDLBase<ConvertMathToROCDLPass> {
+  using impl::ConvertMathToROCDLBase<
+      ConvertMathToROCDLPass>::ConvertMathToROCDLBase;
+
   void runOnOperation() override;
 };
-} // namespace
 
 void ConvertMathToROCDLPass::runOnOperation() {
   auto m = getOperation();
   MLIRContext *ctx = m.getContext();
+  FailureOr<amdgpu::Chipset> maybeChipset = amdgpu::Chipset::parse(chipset);
 
   RewritePatternSet patterns(&getContext());
   LowerToLLVMOptions options(ctx, DataLayout(m));
   LLVMTypeConverter converter(ctx, options);
-  populateMathToROCDLConversionPatterns(converter, patterns);
+  populateMathToROCDLConversionPatterns(converter, patterns, *maybeChipset);
   ConversionTarget target(getContext());
-  target.addLegalDialect<BuiltinDialect, func::FuncDialect,
-                         vector::VectorDialect, LLVM::LLVMDialect>();
+  target
+      .addLegalDialect<BuiltinDialect, func::FuncDialect, vector::VectorDialect,
+                       LLVM::LLVMDialect, ROCDL::ROCDLDialect>();
   target.addIllegalOp<LLVM::CosOp, LLVM::ExpOp, LLVM::Exp2Op, LLVM::FAbsOp,
                       LLVM::FCeilOp, LLVM::FFloorOp, LLVM::FRemOp, LLVM::LogOp,
                       LLVM::Log10Op, LLVM::Log2Op, LLVM::PowOp, LLVM::SinOp,

mlir/test/Conversion/MathToROCDL/math-to-rocdl.mlir

@@ -1,4 +1,5 @@
-// RUN: mlir-opt %s -convert-math-to-rocdl -allow-unregistered-dialect -split-input-file | FileCheck %s
+// RUN: mlir-opt %s -allow-unregistered-dialect -split-input-file -pass-pipeline='builtin.module(convert-math-to-rocdl{chipset=gfx803})' | FileCheck %s --check-prefix=PRE9
+// RUN: mlir-opt %s -allow-unregistered-dialect -split-input-file -pass-pipeline='builtin.module(convert-math-to-rocdl{chipset=gfx942})' | FileCheck %s --check-prefix=POST9
 
 module @test_module {
   // CHECK: llvm.func @__ocml_fmod_f16(f16, f16) -> f16
@@ -596,3 +597,32 @@ module @test_module {
     func.return %result : vector<2x2xf16>
   }
 }
+
+// -----
+
+// f16 clamp → rocdl.fmed3 on gfx9+
+func.func @clampf_f16(%x: f16, %lo: f16, %hi: f16) -> f16 {
+  %r = math.clampf %x to [%lo, %hi] : f16
+  return %r : f16
+}
+
+// f32 clamp → rocdl.fmed3 on gfx9+
+func.func @clampf_f32(%x: f32, %lo: f32, %hi: f32) -> f32 {
+  %r = math.clampf %x to [%lo, %hi] : f32
+  return %r : f32
+}
+
+// POST9-LABEL: func.func @clampf_f16
+// POST9: rocdl.fmed3 {{.*}} : f16
+// POST9: return
+
+// POST9-LABEL: func.func @clampf_f32
+// POST9: rocdl.fmed3 {{.*}} : f32
+// POST9: return
+
+// PRE9-LABEL: func.func @clampf_f16
+// PRE9-NOT: rocdl.fmed3
+// PRE9: math.clampf {{.*}} : f16
+
+// PRE9-LABEL: func.func @clampf_f32
+// PRE9-NOT: rocdl.fmed3