pow_si.c: another comment about the overflow detection.

git-svn-id: svn://scm.gforge.inria.fr/svn/mpfr/trunk@4355 280ebfd0-de03-0410-8827-d642c229c3f4

1 files changed, 5 insertions, 0 deletions

diff --git a/pow_si.c b/pow_si.c
index 84a73ff55..87a8bc7cc 100644
--- a/pow_si.c
+++ b/pow_si.c
@@ -112,6 +112,11 @@ mpfr_pow_si (mpfr_ptr y, mpfr_srcptr x, long int n, mp_rnd_t rnd)
            *     overflow since 0 > expx >= (__gmpfr_emax - 1) / n and
            *           0 < n * expx <= n * ((__gmpfr_emax - 1) / n)
            *                        <= __gmpfr_emax - 1.
+           * Note: one could use expx bounds based on MPFR_EXP_MIN and
+           * MPFR_EXP_MAX instead of __gmpfr_emin and __gmpfr_emax. The
+           * current bounds do not lead to noticeably slower code and
+           * allow us to avoid a bug in Sun's compiler for Solaris/x86
+           * (when optimizations are enabled).
            */
           expy =
             n != -1 && expx > 0 && expx > (__gmpfr_emin - 1) / n ?