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[Guile-commits] 01/01: Fix (* x -1) for GOOPS types
From: |
Andy Wingo |
Subject: |
[Guile-commits] 01/01: Fix (* x -1) for GOOPS types |
Date: |
Tue, 28 Feb 2017 04:15:06 -0500 (EST) |
wingo pushed a commit to branch master
in repository guile.
commit 70d4c4b284ba85d89969d8da43f80ff66f491e37
Author: Andy Wingo <address@hidden>
Date: Tue Feb 28 10:12:57 2017 +0100
Fix (* x -1) for GOOPS types
* libguile/numbers.c (scm_product): Only reduce (* x -1) to (- x) when X
is a bignum. Fixes weirdness when X is not a number and instead
multiplication should dispatch to GOOPS. Thanks to Alejandro Sanchez
for the report.
---
libguile/numbers.c | 28 +++++++++++++---------------
1 file changed, 13 insertions(+), 15 deletions(-)
diff --git a/libguile/numbers.c b/libguile/numbers.c
index 99b564e..0d053c8 100644
--- a/libguile/numbers.c
+++ b/libguile/numbers.c
@@ -8021,17 +8021,6 @@ scm_product (SCM x, SCM y)
else
return scm_wta_dispatch_2 (g_product, x, y, SCM_ARGn, s_product);
break;
- case -1:
- /*
- * This case is important for more than just optimization.
- * It handles the case of negating
- * (+ 1 most-positive-fixnum) aka (- most-negative-fixnum),
- * which is a bignum that must be changed back into a fixnum.
- * Failure to do so will cause the following to return #f:
- * (= most-negative-fixnum (* -1 (- most-negative-fixnum)))
- */
- return scm_difference(y, SCM_UNDEFINED);
- break;
}
if (SCM_LIKELY (SCM_I_INUMP (y)))
@@ -8056,10 +8045,19 @@ scm_product (SCM x, SCM y)
}
else if (SCM_BIGP (y))
{
- SCM result = scm_i_mkbig ();
- mpz_mul_si (SCM_I_BIG_MPZ (result), SCM_I_BIG_MPZ (y), xx);
- scm_remember_upto_here_1 (y);
- return result;
+ /* There is one bignum which, when multiplied by negative one,
+ becomes a non-zero fixnum: (1+ most-positive-fixum). Since
+ we know the type of X and Y are numbers, delegate this
+ special case to scm_difference. */
+ if (xx == -1)
+ return scm_difference (y, SCM_UNDEFINED);
+ else
+ {
+ SCM result = scm_i_mkbig ();
+ mpz_mul_si (SCM_I_BIG_MPZ (result), SCM_I_BIG_MPZ (y), xx);
+ scm_remember_upto_here_1 (y);
+ return result;
+ }
}
else if (SCM_REALP (y))
return scm_i_from_double (xx * SCM_REAL_VALUE (y));