[clang] [OpenCL] Add cl_khr_fp64 guard for atomic_double/double in cl_ext_float_atomics functions (PR #169252)

[Wenju He via cfe-commits]

https://github.com/wenju-he created https://github.com/llvm/llvm-project/pull/169252

Fix kernel build when cl_khr_fp64 is not enabled:
opencl-c.h:13785:50: error: unknown type name 'atomic_double'
 13785 | double __ovld atomic_fetch_min(volatile __global atomic_double *, double);
opencl-c.h:13785:67: error: use of type 'double' requires cl_khr_fp64 and __opencl_c_fp64 support
 13785 | double __ovld atomic_fetch_min(volatile __global atomic_double *, double);

This is a regression introduced by 423bdb2b. Before that commit, __opencl_c_ext_fp64_global_atomic_add was guarded by cl_khr_fp64 in opencl-c-base.h.

>From 9dddf5de8a06b30bfb2647045a328e9d12fd9567 Mon Sep 17 00:00:00 2001
From: Wenju He <wenju.he at intel.com>
Date: Sun, 23 Nov 2025 14:50:16 -0800
Subject: [PATCH] [OpenCL] Add cl_khr_fp64 guard for atomic_double/double in
 cl_ext_float_atomics functions

Fix kernel build when cl_khr_fp64 is not enabled:
opencl-c.h:13785:50: error: unknown type name 'atomic_double'
 13785 | double __ovld atomic_fetch_min(volatile __global atomic_double *, double);
opencl-c.h:13785:67: error: use of type 'double' requires cl_khr_fp64 and __opencl_c_fp64 support
 13785 | double __ovld atomic_fetch_min(volatile __global atomic_double *, double);

This is a regression introduced by 423bdb2b. Before that commit,
__opencl_c_ext_fp64_global_atomic_add was guarded by cl_khr_fp64 in opencl-c-base.h.
---
 clang/lib/Headers/opencl-c.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/clang/lib/Headers/opencl-c.h b/clang/lib/Headers/opencl-c.h
index f65b4b314cffd..39f91c139496e 100644
--- a/clang/lib/Headers/opencl-c.h
+++ b/clang/lib/Headers/opencl-c.h
@@ -13781,6 +13781,7 @@ float __ovld atomic_fetch_max_explicit(volatile atomic_float *,
     defined(__opencl_c_ext_fp32_local_atomic_min_max)
 
 #if defined(cl_khr_int64_base_atomics) && defined(cl_khr_int64_extended_atomics)
+#ifdef cl_khr_fp64
 #if defined(__opencl_c_ext_fp64_global_atomic_min_max)
 double __ovld atomic_fetch_min(volatile __global atomic_double *, double);
 double __ovld atomic_fetch_max(volatile __global atomic_double *, double);
@@ -13821,6 +13822,7 @@ double __ovld atomic_fetch_max_explicit(volatile atomic_double *,
                                         double, memory_order, memory_scope);
 #endif // defined(__opencl_c_ext_fp64_global_atomic_min_max) &&                \
     defined(__opencl_c_ext_fp64_local_atomic_min_max)
+#endif // cl_khr_fp64
 #endif // defined(cl_khr_int64_base_atomics) &&                                \
     defined(cl_khr_int64_extended_atomics)
 
@@ -13907,6 +13909,7 @@ float __ovld atomic_fetch_sub_explicit(volatile atomic_float *,
     defined(__opencl_c_ext_fp32_local_atomic_add)
 
 #if defined(cl_khr_int64_base_atomics) && defined(cl_khr_int64_extended_atomics)
+#ifdef cl_khr_fp64
 #if defined(__opencl_c_ext_fp64_global_atomic_add)
 double __ovld atomic_fetch_add(volatile __global atomic_double *, double);
 double __ovld atomic_fetch_sub(volatile __global atomic_double *, double);
@@ -13947,6 +13950,7 @@ double __ovld atomic_fetch_sub_explicit(volatile atomic_double *,
                                         double, memory_order, memory_scope);
 #endif // defined(__opencl_c_ext_fp64_global_atomic_add) &&                    \
     defined(__opencl_c_ext_fp64_local_atomic_add)
+#endif // cl_khr_fp64
 #endif // defined(cl_khr_int64_base_atomics) &&                                \
     defined(cl_khr_int64_extended_atomics)