bigrecy patch for 32-bit bignum failures

Cherry-picked a single commit from upstream.

Turns out this bug (which was causing test failures and thus FTBFS on
a subset of platforms) had been identified and fixed upstream a year
ago, but had not made it's way into version control (CVS) or the
Changelog.

See also:
http://lists.gnu.org/archive/html/scm-discuss/2017-10/msg00009.html

3 files changed, 100 insertions, 0 deletions

diff --git a/debian/changelog b/debian/changelog
index 6361b65..2fd13ad 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,10 @@
+scm (5f2-2) UNRELEASED; urgency=medium
+
+  * Cherry-pick Jakub Bogusz's upstream patch to fix a 32-bit platform bignum
+    bug causing test failures and FTBFS (Closes: #874112)
+
+ -- Bryan Newbold <bnewbold@robocracy.org>  Thu, 12 Oct 2017 21:01:09 -0700
+
 scm (5f2-1) unstable; urgency=medium
 
   * New upstream release (Closes: #791958) with improved floating point
diff --git a/debian/patches/bigrecy_32bit_upstream.patch b/debian/patches/bigrecy_32bit_upstream.patch
new file mode 100644
index 0000000..c103141
--- /dev/null
+++ b/debian/patches/bigrecy_32bit_upstream.patch
@@ -0,0 +1,92 @@
+Description: Support ARM64 ("aarch64") platform
+Author: Jakub Bogusz
+--- a/scl.c	2015/01/03 20:50:15	1.142
++++ b/scl.c	2016/08/10 02:33:05	1.143
+@@ -166,33 +166,34 @@
+     /* try first with starved precision */
+     {
+       num = scm_ash(mant, MAKINUM(e2 - point));
+-      bigrecy(mant);
++      if (num != mant) bigrecy(mant);
+       quo = scm_round_quotient(num, VELTS(pows5)[(long) point]);
+       if (pmantexp2dbl(quo, point) != f) {
+-	bigrecy(quo); quo = num;
++	if (quo != num) { bigrecy(quo); quo = num; }
+ 	num = scm_ash(quo, MAKINUM(1L));
+-	bigrecy(quo);
++	if (num != quo) bigrecy(quo);
+ 	quo = scm_round_quotient(num, VELTS(pows5)[(long) --point]);
+       }
++      if (num != quo) bigrecy(num);
+     }
+   } else {   /* e2 <= 0 */
+     /* try first with starved precision */
+     {
+       SCM den = scm_ash(MAKINUM(1L), MAKINUM(point - e2));
+       num = product(mant, VELTS(pows5)[- (long) point]);
+-      bigrecy(mant);
++      if (num != mant) { bigrecy(mant); if (mant != MAKINUM(1)) mant = INUM0; }
+       quo = scm_round_quotient(num, den);
+       if (pmantexp2dbl(quo, point) != f) {
+-	bigrecy(quo); quo = num;
++	if (quo != num) { bigrecy(quo); quo = num; }
+ 	point--;
+ 	num = product(quo, MAKINUM(10));
+ 	if (mant != MAKINUM(1)) bigrecy(quo);
+ 	quo = scm_round_quotient(num, den);
+-      }
++	if (quo != num) bigrecy(num);
++      } else if ((mant != MAKINUM(1)) && (quo != num)) bigrecy(num);
+       bigrecy(den);
+     }
+   }
+-  bigrecy(num);
+   a[ch++] = '.';
+   /* if (sizeof(UBIGLONG)>=sizeof(double)) /\* Is ulong larger than mantissa? *\/ */
+   /*   ch += iulong2str(num2ulong(quo, (char *)ARG1, s_number2string), 10, &a[ch]); */
+@@ -680,7 +681,7 @@
+       ans = ldexp(ans, bex + point);
+     }
+     if (num != quo) bigrecy(quo);
+-    if (bmant != MAKINUM(1L)) bigrecy(num);
++    if ((num != bmant) && (bmant != MAKINUM(1L))) bigrecy(num);
+     return ans;
+   } else {
+     int maxpow = LENGTH(pows5) - 1;
+@@ -696,7 +697,7 @@
+       quo = scm_round_quotient(num, scm_ash(scl, MAKINUM(1L)));
+     }
+     if (-point > maxpow) bigrecy(scl);
+-    bigrecy(num);
++    if (num != quo) bigrecy(num);
+     ans = ldexp(int2dbl(quo), bex + point);
+     bigrecy(quo);
+     return ans;
+@@ -2478,7 +2479,7 @@
+ 	tmp = acc;
+ 	acc = product(tmp, tz1);
+ #ifdef BIGDIG
+-	bigrecy(tmp);
++	if (acc != tmp) bigrecy(tmp);
+ #endif
+ 	break;
+       }
+@@ -2486,7 +2487,7 @@
+ 	tmp = acc;
+ 	acc = product(tmp, tz1);
+ #ifdef BIGDIG
+-	bigrecy(tmp);
++	if (acc != tmp) bigrecy(tmp);
+ #endif
+       }
+       tmp = tz1;
+@@ -2841,8 +2842,8 @@
+       bex += j * BITSPERDIG;
+       if (bex > 0) ans = ldexp(ans, bex);
+     }
++    if (quo != num) bigrecy(quo);
+     if (num != b) bigrecy(num);
+-    if (quo != b) bigrecy(quo);
+     if (tc16_bigneg==TYP16(b)) return -ans;
+     return ans;
+   }
diff --git a/debian/patches/series b/debian/patches/series
index 102a07f..2f25f43 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -4,3 +4,4 @@ texinfo5_fixes.patch
 ppc64_short_int.patch
 arm64_short_int.patch
 hurd_maxpathlen.patch
+bigrecy_32bit_upstream.patch