[Flang][LoongArch] Add support for complex16 params/returns.

[ylzsx]

In LoongArch64, the passing and returning of type complex16 is similar
to that of structure type like struct {fp128, fp128}, meaning they are
passed and returned by reference. This behavior is similar to clang, so
it can implement conveniently iso_c_binding.

Additionally, this patch fixes the failure in flang test
Integration/debug-complex-1.f90:

llvm-project/flang/lib/Optimizer/codeGen/Target.cpp:56:
not yet implemented: complex for this precision for return type

[llvmbot]

@llvm/pr-subscribers-flang-fir-hlfir

@llvm/pr-subscribers-flang-codegen

Author: Zhaoxin Yang (ylzsx)

Changes

This patch fixes the failure in flang test Integration/debug-complex-1.f90:

llvm-project/flang/lib/Optimizer/codeGen/Target.cpp:56:
not yet implemented: complex for this precision for return type

---

Full diff: https://github.com/llvm/llvm-project/pull/114732.diff

1 Files Affected:

• (modified) flang/lib/Optimizer/CodeGen/Target.cpp (+4-2)

diff --git a/flang/lib/Optimizer/CodeGen/Target.cpp b/flang/lib/Optimizer/CodeGen/Target.cpp
index 6c148dffb0e55a..43a039e46d143d 100644
--- a/flang/lib/Optimizer/CodeGen/Target.cpp
+++ b/flang/lib/Optimizer/CodeGen/Target.cpp
@@ -1087,7 +1087,8 @@ struct TargetLoongArch64 : public GenericTarget<TargetLoongArch64> {
     CodeGenSpecifics::Marshalling marshal;
     const auto *sem = &floatToSemantics(kindMap, eleTy);
     if (sem == &llvm::APFloat::IEEEsingle() ||
-        sem == &llvm::APFloat::IEEEdouble()) {
+        sem == &llvm::APFloat::IEEEdouble() ||
+        sem == &llvm::APFloat::IEEEquad()) {
       // Two distinct element type arguments (re, im)
       marshal.emplace_back(eleTy, AT{});
       marshal.emplace_back(eleTy, AT{});
@@ -1102,7 +1103,8 @@ struct TargetLoongArch64 : public GenericTarget<TargetLoongArch64> {
     CodeGenSpecifics::Marshalling marshal;
     const auto *sem = &floatToSemantics(kindMap, eleTy);
     if (sem == &llvm::APFloat::IEEEsingle() ||
-        sem == &llvm::APFloat::IEEEdouble()) {
+        sem == &llvm::APFloat::IEEEdouble() ||
+        sem == &llvm::APFloat::IEEEquad()) {
       // Use a type that will be translated into LLVM as:
       // { t, t }   struct of 2 eleTy, byVal
       marshal.emplace_back(mlir::TupleType::get(eleTy.getContext(),

[tblah]

LGTM, thanks!