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From: Alexander Monakov <amonakov@ispras.ru>
To: musl@lists.openwall.com
Cc: "Alex Rønne Petersen" <alex@alexrp.com>
Subject: Re: [musl] [PATCH] configure: prevent compilers from turning a * b + c into fma(a, b, c)
Date: Thu, 29 Aug 2024 00:11:03 +0300 (MSK)	[thread overview]
Message-ID: <d6e3c806-1ce4-2ece-3360-df0a90c777f9@ispras.ru> (raw)
In-Reply-To: <20240828204725.GI10433@brightrain.aerifal.cx>


On Wed, 28 Aug 2024, Rich Felker wrote:

> I'm not clear on why the -mno-fused-madd would be needed. It should be
> a no-op with -ffp-contract=off unless __builtin_fma were called
> explicitly or something, no?

I think Glibc was applying it as a workaround for old GCC releases where
target backends were doing unrestricted contraction, or -ffp-contract=
option did not exist in the first place.

Alexander

  reply	other threads:[~2024-08-28 21:11 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-08-28 15:28 Alex Rønne Petersen
2024-08-28 15:53 ` Alexander Monakov
2024-08-28 16:31   ` Alex Rønne Petersen
2024-08-28 20:15   ` Rich Felker
2024-08-28 20:32     ` Alexander Monakov
2024-08-28 20:47       ` Rich Felker
2024-08-28 21:11         ` Alexander Monakov [this message]
2024-08-29 13:37           ` Alex Rønne Petersen
2024-08-28 19:56 ` Alexander Monakov
2024-08-29 13:36   ` Alex Rønne Petersen
2024-08-29 15:09     ` Alexander Monakov

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