[PATCH] D112053: [cuda] Add address space predicate funuctions.

[Michael Liao via Phabricator via cfe-commits]

hliao added inline comments.


================
Comment at: clang/include/clang/Basic/BuiltinsNVPTX.def:691-694
+BUILTIN(__nvvm_isspacep_const, "bvC*", "nc")
+BUILTIN(__nvvm_isspacep_global, "bvC*", "nc")
+BUILTIN(__nvvm_isspacep_local, "bvC*", "nc")
+BUILTIN(__nvvm_isspacep_shared, "bvC*", "nc")
----------------
tra wrote:
> CUDA appears to be using `__nv_isGlobal_impl` for the AS predicates. Perhaps we want to add those, too, forwarding them to the `__nvvm_...` implementations above. I've already added a few other AS-related `__nv_*` builtins in `lib/Headers/__clang_cuda_intrinsics.h`.
`__nv_isGlobal_impl` is exposed as an official interface. In fact, in CUDA SDK 10.0 or earlier, `__isGlobal` is directly implemented as inline asm. If possible, we should avoid defining unofficial or undocumented interfaces. `__nv_isGlobal_impl` was introduced from CUDA SDK 10.1 but there is no documentation on it.

  // This function returns 1 if generic address "ptr" is in global memory space.
  // It returns 0 if "ptr" is in shared, local or constant memory space.
  __SM_20_INTRINSICS_DECL__ unsigned int __isGlobal(const void *ptr)
  {
    unsigned int ret;
    asm volatile ("{ \n\t"
                  "    .reg .pred p; \n\t"
                  "    isspacep.global p, %1; \n\t"
                  "    selp.u32 %0, 1, 0, p;  \n\t"
  #if (defined(_MSC_VER) && defined(_WIN64)) || defined(__LP64__) || defined(__CUDACC_RTC__)
                  "} \n\t" : "=r"(ret) : "l"(ptr));
  #else
                  "} \n\t" : "=r"(ret) : "r"(ptr));
  #endif

    return ret;
  }



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https://reviews.llvm.org/D112053