[compiler-rt] [llvm] Reland "[X86][BF16] Add libcall for F80 -> BF16 (#109116)" (PR #109143)

[Phoebe Wang via llvm-commits]

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@@ -0,0 +1,16 @@
+//===-- lib/truncxfbf2.c - long double -> bfloat conversion -------*- C -*-===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#if defined(CRT_HAS_TF_MODE) && __LDBL_MANT_DIG__ == 64 && defined(__x86_64__)
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phoebewang wrote:

I assume this would solve the buildbot failures on other targets, but I'm surprised it was also failed on `llvm-clang-x86_64-gcc-ubuntu`. I'll check it locally tomorrow.

https://github.com/llvm/llvm-project/pull/109143