Extend

Author: victor-eds

mlir/include/mlir/Conversion/ArithCommon/AttrToLLVMConverter.h

@@ -103,6 +103,41 @@ class AttrConvertOverflowToLLVM {
 private:
   NamedAttrList convertedAttr;
 };
+
+template <typename SourceOp, typename TargetOp>
+class AttrConverterConstrainedFPToLLVM {
+  static_assert(TargetOp::template hasTrait<
+                    LLVM::FPExceptionBehaviorOpInterface::Trait>(),
+                "Target constrained FP operations must implement "
+                "LLVM::FPExceptionBehaviorOpInterface");
+
+public:
+  AttrConverterConstrainedFPToLLVM(
+      SourceOp srcOp) {
+    // Copy the source attributes.
+    convertedAttr = NamedAttrList{srcOp->getAttrs()};
+
+    if constexpr (TargetOp::template hasTrait<
+                      LLVM::RoundingModeOpInterface::Trait>()) {
+      // Get the name of the rounding mode attribute.
+      StringRef arithAttrName = srcOp.getRoundingModeAttrName();
+      // Remove the source attribute.
+      auto arithAttr =
+          cast<arith::RoundingModeAttr>(convertedAttr.erase(arithAttrName));
+      // Set the target attribute.
+      convertedAttr.set(TargetOp::getRoundingModeAttrName(),
+                        convertArithRoundingModeAttrToLLVM(arithAttr));
+    }
+    convertedAttr.set(TargetOp::getFPExceptionBehaviorAttrName(),
+                      getLLVMDefaultFPExceptionBehavior(*srcOp->getContext()));
+  }
+
+  ArrayRef<NamedAttribute> getAttrs() const { return convertedAttr.getAttrs(); }
+
+private:
+  NamedAttrList convertedAttr;
+};
+
 } // namespace arith
 } // namespace mlir
 

mlir/lib/Conversion/ArithToLLVM/ArithToLLVM.cpp

@@ -139,6 +139,9 @@ using SubIOpLowering =
 using TruncFOpLowering =
     ConstrainedVectorConvertToLLVMPattern<arith::TruncFOp, LLVM::FPTruncOp,
                                           false>;
+using ConstrainedTruncFOpLowering = ConstrainedVectorConvertToLLVMPattern<
+    arith::TruncFOp, LLVM::ConstrainedFPTruncIntr, true,
+    arith::AttrConverterConstrainedFPToLLVM>;
 using TruncIOpLowering =
     VectorConvertToLLVMPattern<arith::TruncIOp, LLVM::TruncOp>;
 using UIToFPOpLowering =
@@ -563,6 +566,7 @@ void mlir::arith::populateArithToLLVMConversionPatterns(
     SubFOpLowering,
     SubIOpLowering,
     TruncFOpLowering,
+    ConstrainedTruncFOpLowering,
     TruncIOpLowering,
     UIToFPOpLowering,
     XOrIOpLowering

mlir/test/Conversion/ArithToLLVM/arith-to-llvm.mlir

@@ -289,6 +289,21 @@ func.func @fptrunc_vector(%arg0 : vector<2xf32>, %arg1 : vector<2xf64>) {
   return
 }
 
+// CHECK-LABEL: experimental_constrained_fptrunc
+func.func @experimental_constrained_fptrunc(%arg0 : f64) {
+// CHECK-NEXT: = llvm.intr.experimental.constrained.fptrunc {{.*}} tonearest ignore : f64 to f32
+  %0 = arith.truncf %arg0 tonearesteven : f64 to f32
+// CHECK-NEXT: = llvm.intr.experimental.constrained.fptrunc {{.*}} downward ignore : f64 to f32
+  %1 = arith.truncf %arg0 downward : f64 to f32
+// CHECK-NEXT: = llvm.intr.experimental.constrained.fptrunc {{.*}} upward ignore : f64 to f32
+  %2 = arith.truncf %arg0 upward : f64 to f32
+// CHECK-NEXT: = llvm.intr.experimental.constrained.fptrunc {{.*}} towardzero ignore : f64 to f32
+  %3 = arith.truncf %arg0 towardzero : f64 to f32
+// CHECK-NEXT: = llvm.intr.experimental.constrained.fptrunc {{.*}} tonearestaway ignore : f64 to f32
+  %4 = arith.truncf %arg0 tonearestaway : f64 to f32
+  return
+}
+
 // Check sign and zero extension and truncation of integers.
 // CHECK-LABEL: @integer_extension_and_truncation
 func.func @integer_extension_and_truncation(%arg0 : i3) {