[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 ↗

(On Diff #321400)

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 ↗

(On Diff #321400)

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

clang/lib/Sema/SemaTemplateDeduction.cpp

     //   "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);
     }