[flang-commits] [flang] [flang] Lower REDUCE intrinsic with no DIM argument and rank 1 (PR #94652)

[via flang-commits]

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@@ -5705,7 +5705,63 @@ void IntrinsicLibrary::genRandomSeed(llvm::ArrayRef<fir::ExtendedValue> args) {
 fir::ExtendedValue
 IntrinsicLibrary::genReduce(mlir::Type resultType,
                             llvm::ArrayRef<fir::ExtendedValue> args) {
-  TODO(loc, "intrinsic: reduce");
+  assert(args.size() == 6);
+
+  fir::BoxValue arrayTmp = builder.createBox(loc, args[0]);
+  mlir::Value array = fir::getBase(arrayTmp);
+  mlir::Value operation = fir::getBase(args[1]);
+  int rank = arrayTmp.rank();
+  assert(rank >= 1);
+
+  mlir::Type ty = array.getType();
+  mlir::Type arrTy = fir::dyn_cast_ptrOrBoxEleTy(ty);
+  mlir::Type eleTy = mlir::cast<fir::SequenceType>(arrTy).getEleTy();
+
+  // Handle optional mask argument
+  bool absentDim = isStaticallyAbsent(args[1]);
+
+  auto mask = isStaticallyAbsent(args[3])
+                  ? builder.create<fir::AbsentOp>(
+                        loc, fir::BoxType::get(builder.getI1Type()))
+                  : builder.createBox(loc, args[3]);
+
+  mlir::Value identity =
+      isStaticallyAbsent(args[4])
+          ? builder.create<fir::AbsentOp>(loc, fir::ReferenceType::get(eleTy))
+          : fir::getBase(args[4]);
+
+  mlir::Value ordered = isStaticallyAbsent(args[5])
+                            ? builder.createBool(loc, true)
----------------
jeanPerier wrote:

I think "false" is the correct default here.
The standard says: "if ORDERED is present with the value true, x and y shall be the first two elements of the sequence.". So the implicit otherwise seems to be ORERED is absent or false, hence absent would be the same as OREDRED=false.

@klausler to double check this since this is different from the runtime API default value.

https://github.com/llvm/llvm-project/pull/94652