Complex Long Double classification In RegCall calling convention

This change is part of the RegCall calling convention support for LLVM. 
Existing RegCall implementation was extended to include correct handling of 
Complex Long Double type. Complex long double types should be returned/passed 
in memory and not register stack. This patch implements this behavior.

Patch by: eandrews

Differential Revision: https://reviews.llvm.org/D35259

llvm-svn: 308769
diff --git a/clang/lib/CodeGen/TargetInfo.cpp b/clang/lib/CodeGen/TargetInfo.cpp
index af23769..23874e3 100644
--- a/clang/lib/CodeGen/TargetInfo.cpp
+++ b/clang/lib/CodeGen/TargetInfo.cpp
@@ -882,8 +882,14 @@
 /// X86_VectorCall calling convention. Shared between x86_32 and x86_64.
 static bool isX86VectorTypeForVectorCall(ASTContext &Context, QualType Ty) {
   if (const BuiltinType *BT = Ty->getAs<BuiltinType>()) {
-    if (BT->isFloatingPoint() && BT->getKind() != BuiltinType::Half)
+    if (BT->isFloatingPoint() && BT->getKind() != BuiltinType::Half) {
+      if (BT->getKind() == BuiltinType::LongDouble) {
+        if (&Context.getTargetInfo().getLongDoubleFormat() ==
+            &llvm::APFloat::x87DoubleExtended())
+          return false;
+      }
       return true;
+    }
   } else if (const VectorType *VT = Ty->getAs<VectorType>()) {
     // vectorcall can pass XMM, YMM, and ZMM vectors. We don't pass SSE1 MMX
     // registers specially.
@@ -3515,18 +3521,27 @@
   unsigned FreeSSERegs = IsRegCall ? 16 : 8;
   unsigned NeededInt, NeededSSE;
 
-  if (IsRegCall && FI.getReturnType()->getTypePtr()->isRecordType() &&
-      !FI.getReturnType()->getTypePtr()->isUnionType()) {
-    FI.getReturnInfo() =
-        classifyRegCallStructType(FI.getReturnType(), NeededInt, NeededSSE);
-    if (FreeIntRegs >= NeededInt && FreeSSERegs >= NeededSSE) {
-      FreeIntRegs -= NeededInt;
-      FreeSSERegs -= NeededSSE;
-    } else {
-      FI.getReturnInfo() = getIndirectReturnResult(FI.getReturnType());
-    }
-  } else if (!getCXXABI().classifyReturnType(FI))
-    FI.getReturnInfo() = classifyReturnType(FI.getReturnType());
+  if (!getCXXABI().classifyReturnType(FI)) {
+    if (IsRegCall && FI.getReturnType()->getTypePtr()->isRecordType() &&
+        !FI.getReturnType()->getTypePtr()->isUnionType()) {
+      FI.getReturnInfo() =
+          classifyRegCallStructType(FI.getReturnType(), NeededInt, NeededSSE);
+      if (FreeIntRegs >= NeededInt && FreeSSERegs >= NeededSSE) {
+        FreeIntRegs -= NeededInt;
+        FreeSSERegs -= NeededSSE;
+      } else {
+        FI.getReturnInfo() = getIndirectReturnResult(FI.getReturnType());
+      }
+    } else if (IsRegCall && FI.getReturnType()->getAs<ComplexType>()) {
+      // Complex Long Double Type is passed in Memory when Regcall
+      // calling convention is used.
+      const ComplexType *CT = FI.getReturnType()->getAs<ComplexType>();
+      if (getContext().getCanonicalType(CT->getElementType()) ==
+          getContext().LongDoubleTy)
+        FI.getReturnInfo() = getIndirectReturnResult(FI.getReturnType());
+    } else
+      FI.getReturnInfo() = classifyReturnType(FI.getReturnType());
+  }
 
   // If the return value is indirect, then the hidden argument is consuming one
   // integer register.