[llvm-branch-commits] [flang] [flang][OpenMP] lower simple array reductions (PR #84958)

[Kiran Chandramohan via llvm-branch-commits]

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@@ -92,10 +93,42 @@ std::string ReductionProcessor::getReductionName(llvm::StringRef name,
   if (isByRef)
     byrefAddition = "_byref";
 
-  return (llvm::Twine(name) +
-          (ty.isIntOrIndex() ? llvm::Twine("_i_") : llvm::Twine("_f_")) +
-          llvm::Twine(ty.getIntOrFloatBitWidth()) + byrefAddition)
-      .str();
+  if (fir::isa_trivial(ty))
+    return (llvm::Twine(name) +
+            (ty.isIntOrIndex() ? llvm::Twine("_i_") : llvm::Twine("_f_")) +
+            llvm::Twine(ty.getIntOrFloatBitWidth()) + byrefAddition)
+        .str();
+
+  // creates a name like reduction_i_64_box_ux4x3
+  if (auto boxTy = mlir::dyn_cast_or_null<fir::BaseBoxType>(ty)) {
+    // TODO: support for allocatable boxes:
+    // !fir.box<!fir.heap<!fir.array<...>>>
+    fir::SequenceType seqTy = fir::unwrapRefType(boxTy.getEleTy())
+                                  .dyn_cast_or_null<fir::SequenceType>();
+    if (!seqTy)
+      return {};
+
+    std::string prefix = getReductionName(
+        name, fir::unwrapSeqOrBoxedSeqType(ty), /*isByRef=*/false);
+    if (prefix.empty())
+      return {};
+    std::stringstream tyStr;
+    tyStr << prefix << "_box_";
+    bool first = true;
+    for (std::int64_t extent : seqTy.getShape()) {
+      if (first)
+        first = false;
+      else
+        tyStr << "x";
+      if (extent == seqTy.getUnknownExtent())
+        tyStr << 'u'; // I'm not sure that '?' is safe in symbol names
+      else
+        tyStr << extent;
+    }
+    return (tyStr.str() + byrefAddition).str();
+  }
+
+  return {};
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kiranchandramohan wrote:

There is a getTypeAsString (https://github.com/llvm/llvm-project/blob/07b18c5e1b7a8ac9347f945da5ffaecc4515f391/flang/lib/Optimizer/Dialect/FIRType.cpp#L520). Can that be used? If it changes existing reduction names then we can move to this in a separate patch.

https://github.com/llvm/llvm-project/pull/84958