>From cfd5e106c3c9334de93ccda0d65523476553fb1f Mon Sep 17 00:00:00 2001
From: Paul Eggert <eggert@cs.ucla.edu>
Date: Tue, 26 May 2020 00:47:24 -0700
Subject: [PATCH] Port struct Lisp_FLoat to oddball platforms
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* src/lisp.h (struct Lisp_Float): Declare via
GCALIGNED_UNION_MEMBER, not via GCALIGNED_STRUCT, since alloc.c
creates these in arrays and GCALIGNED_STRUCT does not necessarily
suffice to align struct Lisp_Float when it’s used in an array.
This avoids undefined behavior on oddball machines where
sizeof (struct Lisp_Float) is not a multiple of 8 and the compiler
does not support __attribute__ ((aligned 8)).
---
 src/lisp.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/lisp.h b/src/lisp.h
index 8bd83a888c..f5d581a2f1 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -2801,8 +2801,10 @@ XBUFFER_OBJFWD (lispfwd a)
     {
       double data;
       struct Lisp_Float *chain;
+      GCALIGNED_UNION_MEMBER
     } u;
-  } GCALIGNED_STRUCT;
+  };
+verify (GCALIGNED (struct Lisp_Float));
 
 INLINE bool
 (FLOATP) (Lisp_Object x)
-- 
2.17.1