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From: "iains at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/111876] bf16 complex mul/div does not work when the
 target has +fp16 support or when -fexcess-precision=16 is supplied
Date: Thu, 19 Oct 2023 22:12:30 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D111876

--- Comment #5 from Iain Sandoe <iains at gcc dot gnu.org> ---
for the record an __fp16 implementation works as expected;

* when the target does not support +fp16, the code-gen promotes to float and
does the multiply with __mulsc3

* when the target supports +fp16, the code-gen uses __mulhc3 (which is
implemented in libgcc)

* adding "+bf16" does not affect this.

---

So the issue is that __bf16 works when there is no support for a 16b float,
(because, like fp16, it gets promoted) - but fails when the target declares
support for a different 16 float.=