[NVPTX] Update ABI handling

For PTX, we want the target to handle struct returns directly.

llvm-svn: 195268

Author: jholewinski-nv

clang/lib/CodeGen/TargetInfo.cpp

@@ -4197,16 +4197,26 @@ class NVPTXTargetCodeGenInfo : public TargetCodeGenInfo {
 ABIArgInfo NVPTXABIInfo::classifyReturnType(QualType RetTy) const {
   if (RetTy->isVoidType())
     return ABIArgInfo::getIgnore();
-  if (isAggregateTypeForABI(RetTy))
-    return ABIArgInfo::getIndirect(0);
-  return ABIArgInfo::getDirect();
+
+  // note: this is different from default ABI
+  if (!RetTy->isScalarType())
+    return ABIArgInfo::getDirect();
+
+  // Treat an enum type as its underlying type.
+  if (const EnumType *EnumTy = RetTy->getAs<EnumType>())
+    RetTy = EnumTy->getDecl()->getIntegerType();
+
+  return (RetTy->isPromotableIntegerType() ?
+          ABIArgInfo::getExtend() : ABIArgInfo::getDirect());
 }
 
 ABIArgInfo NVPTXABIInfo::classifyArgumentType(QualType Ty) const {
-  if (isAggregateTypeForABI(Ty))
-    return ABIArgInfo::getIndirect(0);
+  // Treat an enum type as its underlying type.
+  if (const EnumType *EnumTy = Ty->getAs<EnumType>())
+    Ty = EnumTy->getDecl()->getIntegerType();
 
-  return ABIArgInfo::getDirect();
+  return (Ty->isPromotableIntegerType() ?
+          ABIArgInfo::getExtend() : ABIArgInfo::getDirect());
 }
 
 void NVPTXABIInfo::computeInfo(CGFunctionInfo &FI) const {

clang/test/CodeGen/nvptx-abi.c

@@ -0,0 +1,17 @@
+// RUN: %clang_cc1 -triple nvptx-unknown-unknown -S -o - %s -emit-llvm | FileCheck %s
+// RUN: %clang_cc1 -triple nvptx64-unknown-unknown -S -o - %s -emit-llvm | FileCheck %s
+
+typedef struct float4_s {
+  float x, y, z, w;
+} float4_t;
+
+float4_t my_function(void);
+
+// CHECK-DAG: declare %struct.float4_s @my_function
+
+float bar(void) {
+  float4_t ret;
+// CHECK-DAG: call %struct.float4_s @my_function
+  ret = my_function();
+  return ret.x;
+}