[libclc] libclc: Replace nextafter implementation (PR #186082)

[Wenju He via cfe-commits]

================
@@ -0,0 +1,15 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+_CLC_OVERLOAD _CLC_CONST _CLC_DEF __CLC_GENTYPE __clc_nextup(__CLC_GENTYPE x) {
+  __CLC_S_GENTYPE y = __CLC_AS_S_GENTYPE(x + __CLC_FP_LIT(0.0));
----------------
wenju-he wrote:

it seems x + 0.0 flushes denormal to 0

https://github.com/llvm/llvm-project/pull/186082