[OpenCL][PR48896] Fix default address space in template argument deduction

[Anastasia]

Summary

When deducing a reference type for forwarding references prevent adding default address space of a template argument if it is given.

In OpenCL all parameters are in private address space and therefore when we initialize a forwarding reference with a parameter we should just inherit the address space from it i.e. keep __private instead of __generic (see test case).

[Anastasia]

Added test.

[rjmccall]

LGTM.

[bader]

clang/test/SemaOpenCLCXX/address-space-templates.cl

60

This check fails on 32-bit Windows platform where compiler adds __attribute__((thiscall)) both constructor and call operator.

Something like this should fix the problem:

// CHECK: |-CXXConstructorDecl {{.*}} rep 'void (const __generic rep &__private){{.*}} __generic'
// CHECK: CXXMethodDecl {{.*}} operator() 'void (__private int &__private){{.*}} const __generic'

[Anastasia]

clang/test/SemaOpenCLCXX/address-space-templates.cl

60

Sure: https://reviews.llvm.org/D99258

clang/lib/Sema/SemaTemplateDeduction.cpp

if (ParamRefType) {
     if (ArgType->isIncompleteArrayType())
       ArgType = S.getCompletedType(Arg);
 
     // C++1z [temp.deduct.call]p3:
     //   If P is a forwarding reference and the argument is an lvalue, the type
     //   "lvalue reference to A" is used in place of A for type deduction.
     if (isForwardingReference(QualType(ParamRefType, 0), FirstInnerIndex) &&
         Arg->isLValue()) {
-      if (S.getLangOpts().OpenCL)
+      if (S.getLangOpts().OpenCL  && !ArgType.hasAddressSpace())
         ArgType = S.Context.getAddrSpaceQualType(ArgType, LangAS::opencl_generic);
       ArgType = S.Context.getLValueReferenceType(ArgType);
     }
   } else {
     // C++ [temp.deduct.call]p2:
     //   If P is not a reference type:
     //   - If A is an array type, the pointer type produced by the
     //     array-to-pointer standard conversion (4.2) is used in place of

clang/test/SemaOpenCLCXX/address-space-templates.cl

-//RUN: %clang_cc1 %s -cl-std=clc++ -pedantic -verify -fsyntax-only
+//RUN: %clang_cc1 %s -cl-std=clc++ -pedantic -verify -ast-dump  | FileCheck %s
 
 template <typename T>
 struct S {
   T a;        // expected-error{{field may not be qualified with an address space}}
   T f1();     // we ignore address space on a return types.
   void f2(T); // expected-error{{parameter may not be qualified with an address space}}
 };
 

 }
 
 template <class _Tp> struct remove_reference         { typedef _Tp type; };
 template <class _Tp> struct remove_reference<_Tp &>  { typedef _Tp type; };
 template <class _Tp> struct as_pointer {
     typedef typename remove_reference<_Tp>::type* type;
 };
 
+// Check address space deduction in template parameter deduction.
 struct rep {
-  // CHECK |-CXXConstructorDecl {{.*}} rep 'void (const __generic rep &__private) __generic'
+  // When there is no address space on a reference use __generic.
+  // CHECK: |-CXXConstructorDecl {{.*}} rep 'void (const __generic rep &__private) __generic'
   template<class U, class = typename as_pointer<U>::type>
   rep(U&& v) {}
 };
 
 struct rep_outer : private rep {
   rep_outer()
     : rep(0) {}
 };
 
+
+template<class T, class F>
+void foo4(T t, F f){
+  f(t);
+}
+
 void bar() {
   S<const __global int> sintgl; // expected-note{{in instantiation of template class 'S<const __global int>' requested here}}
 
   foo1<__local int>(1); // expected-error{{no matching function for call to 'foo1'}}
   foo2<__global int>(0);
   foo3<__global int>(); // expected-note{{in instantiation of function template specialization 'foo3<__global int>' requested here}}
+
   rep_outer r;
+  int i;
+  // Preserve the address space of the type in forwarding reference.
+  // CHECK: CXXMethodDecl {{.*}} operator() 'void (__private int &__private) const __generic'
+  foo4(i, [](auto&& x){;});
 }