GNU bug report logs - #72145
rare Emacs screwups on x86 due to GCC bug 58416

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Message #39 received at 72145-done <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Pip Cet <pipcet <at> protonmail.com>
Cc: 72145-done <at> debbugs.gnu.org, rms <at> gnu.org
Subject: Re: bug#72145: rare Emacs screwups on x86 due to GCC bug 58416
Date: Fri, 19 Jul 2024 14:31:45 -0700

[Message part 1 (text/plain, inline)]

On 2024-07-18 08:19, Pip Cet wrote:
> It should be mentioned that this isn't just about the CPU: the OS also needs to enable the XMM register set, right?

Right.

In <https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58416#c10> GCC's 
Richard Biener suggested a more portable workaround: use -fno-tree-sra 
when generating 32-bit x86 code for which it is not known that SSE2 is 
supported. (With SSE2, -mfpmath=sse is a better workaround.) Using 
-fno-tree-rsa means we needn't worry whether the build and host 
platforms use different CPU types.

I did that by installing the attached patch to Emacs on savannah, and am 
closing the bug report.

[0001-Work-around-GCC-bug-58416-on-32-bit-x86.patch (text/x-patch, attachment)]

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