From dd5130cadf7252f0bba072109ebfa20cd34a1602 Mon Sep 17 00:00:00 2001
From: Kevin Ryde <user42@zip.com.au>
Date: Tue, 2 Dec 2003 21:21:14 +0000
Subject: [PATCH] (scm_make_ratio): Check for numerator equal to
 SCM_MOST_NEGATIVE_FIXNUM and bignum denominator the negative of that, giving
 integer -1.

---
 libguile/numbers.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/libguile/numbers.c b/libguile/numbers.c
index 50ada27a1..31bd94c32 100644
--- a/libguile/numbers.c
+++ b/libguile/numbers.c
@@ -357,18 +357,26 @@ scm_make_ratio (SCM numerator, SCM denominator)
   */
   if (SCM_INUMP (numerator))
     {
+      long  x = SCM_INUM (numerator);
       if (SCM_EQ_P (numerator, SCM_INUM0))
 	return SCM_INUM0;
       if (SCM_INUMP (denominator))
 	{
-	  long x, y;
-	  x = SCM_INUM (numerator);
+	  long y;
 	  y = SCM_INUM (denominator);
 	  if (x == y)
 	    return SCM_MAKINUM(1);
 	  if ((x % y) == 0)
 	    return SCM_MAKINUM (x / y);
 	}
+      else
+        {
+          /* When x == SCM_MOST_NEGATIVE_FIXNUM we could have the negative
+             of that value for the denominator, as a bignum.  */
+          long  abs_x = (x >= 0 ? x : -x);
+          if (mpz_cmpabs_ui (SCM_I_BIG_MPZ (denominator), abs_x) == 0)
+	    return SCM_MAKINUM(-1);
+        }
     }
   else if (SCM_BIGP (numerator))
     {