On 2016–12–20, at 22:34, Eli Zaretskii <eliz@gnu.org> wrote:

From: Alexis Layton <alexis.layton@post.harvard.edu>
Date: Tue, 20 Dec 2016 21:45:47 -0500

I run the Mac OS (X) binary distributions built by David Caldwell at www.emacsformacosx.com, which claim to be pure GNU Emacs. The latest pretest 25.1.90 immediately crashes on OS X 10.10.5 Yosemite.

$ emacs -nw -q
Illegal instruction: 4

I can't really give much more information. 25.1 and all of its protests and release candidates ran fine, and the released version continues to do so.

It would help if you could run Emacs under a debugger and show
backtrace when it crashes.

Thanks.

Sadly this is not as informative as it looks:

$ lldb /Applications/Emacs.app/Contents/MacOS/Emacs-x86_64-10_9 
(lldb) target create "/Applications/Emacs.app/Contents/MacOS/Emacs-x86_64-10_9"
Current executable set to '/Applications/Emacs.app/Contents/MacOS/Emacs-x86_64-10_9' (x86_64).
(lldb) r
Process 23181 launched: '/Applications/Emacs.app/Contents/MacOS/Emacs-x86_64-10_9' (x86_64)
Process 23181 stopped
* thread #1: tid = 0x1550e6, 0x000000010084979d libnettle.6.dylib`nettle_sha256_init + 4, queue = 'com.apple.main-thread', stop reason = EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)
    frame #0: 0x000000010084979d libnettle.6.dylib`nettle_sha256_init + 4
libnettle.6.dylib`nettle_sha256_init:
->  0x10084979d <+4>:  vmovaps 0x130bb(%rip), %xmm0      ; nettle_sha256_init.H0 + 16
    0x1008497a5 <+12>: vmovups %xmm0, 0x10(%rdi)
    0x1008497aa <+17>: vmovaps 0x1309e(%rip), %xmm0      ; nettle_sha256_init.H0
    0x1008497b2 <+25>: vmovups %xmm0, (%rdi)