[Flang] Add ppc64 support to Optimizer/CodeGen/Target.cpp for AIX 64 bit

[madanial]

Summary

Adding support for ppc64 (big endian) in order to support flang on 64 bit AIX

[clementval]

Can you add a the new triple here flang/test/Fir/target-rewrite-complex.fir and adapt the test?

[madanial]

Add the new triple to flang/test/Fir/target-rewrite-complex.fir as requested. Changed the existing PPC label to be PPC64le and added PPC64 label for the new triple. This is to avoid future confusion with ppc 32 bit.

[madanial]

Ping.

[kiranchandramohan]

The change looks OK to me. Please wait for @clementval incase there are further comments.

[madanial]

Rebase.

flang/lib/Optimizer/CodeGen/Target.cpp

if (sem == &llvm::APFloat::IEEEsingle() ||
       TODO(loc, "complex for this precision");
     }
     return marshal;
   }
 };
 } // namespace
 
 //===----------------------------------------------------------------------===//
+// PPC64 (AIX 64 bit) target specifics.
+//===----------------------------------------------------------------------===//
+
+namespace {
+struct TargetPPC64 : public GenericTarget<TargetPPC64> {
+  using GenericTarget::GenericTarget;
+
+  static constexpr int defaultWidth = 64;
+
+  CodeGenSpecifics::Marshalling
+  complexArgumentType(mlir::Location, mlir::Type eleTy) const override {
+    CodeGenSpecifics::Marshalling marshal;
+    // two distinct element type arguments (re, im)
+    marshal.emplace_back(eleTy, AT{});
+    marshal.emplace_back(eleTy, AT{});
+    return marshal;
+  }
+
+  CodeGenSpecifics::Marshalling
+  complexReturnType(mlir::Location, mlir::Type eleTy) const override {
+    CodeGenSpecifics::Marshalling marshal;
+    // Use a type that will be translated into LLVM as:
+    // { t, t }   struct of 2 element type
+    mlir::TypeRange range = {eleTy, eleTy};
+    marshal.emplace_back(mlir::TupleType::get(eleTy.getContext(), range), AT{});
+    return marshal;
+  }
+};
+} // namespace
+
+//===----------------------------------------------------------------------===//
 // PPC64le linux target specifics.
 //===----------------------------------------------------------------------===//
 
 namespace {
 struct TargetPPC64le : public GenericTarget<TargetPPC64le> {
   using GenericTarget::GenericTarget;
 
   static constexpr int defaultWidth = 64;
case llvm::Triple::ArchType::x86:
     return std::make_unique<TargetI386>(ctx, std::move(trp),
                                         std::move(kindMap));
   case llvm::Triple::ArchType::x86_64:
     return std::make_unique<TargetX86_64>(ctx, std::move(trp),
                                           std::move(kindMap));
   case llvm::Triple::ArchType::aarch64:
     return std::make_unique<TargetAArch64>(ctx, std::move(trp),
                                            std::move(kindMap));
+  case llvm::Triple::ArchType::ppc64:
+    return std::make_unique<TargetPPC64>(ctx, std::move(trp),
+                                         std::move(kindMap));
   case llvm::Triple::ArchType::ppc64le:
     return std::make_unique<TargetPPC64le>(ctx, std::move(trp),
                                            std::move(kindMap));
   case llvm::Triple::ArchType::sparc:
     return std::make_unique<TargetSparc>(ctx, std::move(trp),
                                          std::move(kindMap));
   case llvm::Triple::ArchType::sparcv9:
     return std::make_unique<TargetSparcV9>(ctx, std::move(trp),
                                            std::move(kindMap));
   }
   TODO(mlir::UnknownLoc::get(ctx), "target not implemented");
 }