From: Keith OHara <k-ohara5a5a@oco.net>
Date: Sun, 28 Dec 2014 05:39:55 +0000 (-0800)
Subject: compare LilyPond Rationals without unnecessary overflow; issue 4180
X-Git-Tag: release/2.19.16-1~2^2~38^2~18
X-Git-Url: https://git.donarmstrong.com/?a=commitdiff_plain;h=37756aa46375edb6b2f5af486297278da4358eb3;p=lilypond.git

compare LilyPond Rationals without unnecessary overflow; issue 4180

This reverses part of commit 19125bf1, which said that (r-s).sign() was
too expensive, but I saw no change (within 0.1%) in compilation times.
---

diff --git a/flower/rational.cc b/flower/rational.cc
index a6f82d826e..559e1646a0 100644
--- a/flower/rational.cc
+++ b/flower/rational.cc
@@ -216,11 +216,11 @@ Rational::compare (Rational const &r, Rational const &s)
     return -1;
   else if (r.sign_ > s.sign_)
     return 1;
-  else if (r.is_infinity ())
+  else if (r.is_infinity ()) // here s is also infinite with the same sign
     return 0;
-  else if (r.sign_ == 0)
+  else if (r.sign_ == 0) // here s.sign_ is also zero
     return 0;
-  return r.sign_ * ::sign ((I64) (r.num_ * s.den_) - (I64) (s.num_ * r.den_));
+  return ::sign (r - s);
 }
 
 int