Subject: Re: bug#32477: 27.0.50; `=` burps on bignums when compiled

From: Andy Moreton <[email-masked]>
Date: Mon, 20 Aug 2018 02:37:13 +0100

On Sun 19 Aug 2018, Stefan Monnier wrote:

> Package: Emacs
> Version: 27.0.50
>
> If you try
>
>     M-: (funcall (lambda (x) (= x x)) (expt 2 64)) RET
>
> you'll unsurprisingly get t as result.  Yay!  But if you try
>
>     M-: (funcall (byte-compile '(lambda (x) (= x x))) (expt 2 64)) RET
>
> you should be prompted with an error stating that this largish number is
> not a number-or-marker.  This error occurs for example when loading
> elpa/packages/xelb/xcb-types.elc.

I can reproduce this on a 64bit build on Windows. The following lightly
tested patch appears to work:

diff --git a/src/bytecode.c b/src/bytecode.c
index b27fa7c5c6..155f714a56 100644
--- a/src/bytecode.c
+++ b/src/bytecode.c
@@ -990,8 +990,8 @@ exec_byte_code (Lisp_Object bytestr, Lisp_Object vector, Lisp_Object maxdepth,
 	      TOP = arithcompare (v1, v2, ARITH_EQUAL);
 	    else
 	      {
-		CHECK_FIXNUM_OR_FLOAT_COERCE_MARKER (v1);
-		CHECK_FIXNUM_OR_FLOAT_COERCE_MARKER (v2);
+		CHECK_INTEGER_COERCE_MARKER (v1);
+		CHECK_INTEGER_COERCE_MARKER (v2);
 		TOP = EQ (v1, v2) ? Qt : Qnil;
 	      }
 	    NEXT;