From: Stephen McCamant <smcc@mit.edu>
Date: Fri, 18 Jul 2003 02:26:14 +0000 (-0400)
Subject: Re: Oops - Can't calculate our powers
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=0615a99403886355a89a1cb45b8c609e4424870a;p=p5sagit%2Fp5-mst-13.2.git

Re: Oops - Can't calculate our powers
Message-ID: <16151.37638.162561.84142@syllepsis.MIT.EDU>

p4raw-id: //depot/perl@20167
---

diff --git a/pp.c b/pp.c
index 910101a..537606e 100644
--- a/pp.c
+++ b/pp.c
@@ -972,6 +972,7 @@ PP(pp_pow)
 		    register unsigned int highbit = 8 * sizeof(UV);
 		    register unsigned int lowbit = 0;
 		    register unsigned int diff;
+		    bool odd_power = (power & 1);
 		    while ((diff = (highbit - lowbit) >> 1)) {
 			if (baseuv & ~((1 << (lowbit + diff)) - 1))
 			    lowbit += diff;
@@ -994,7 +995,7 @@ PP(pp_pow)
 			    }
 			}
 			SP--;
-			if (baseuok || !(power & 1))
+			if (baseuok || !odd_power)
 			    /* answer is positive */
 			    SETu( result );
 			else if (result <= (UV)IV_MAX)
diff --git a/t/op/pow.t b/t/op/pow.t
index 2e1d29f..845e0ff 100644
--- a/t/op/pow.t
+++ b/t/op/pow.t
@@ -16,7 +16,10 @@ my @pow = ([3,30,1e-14], [4,32,0], [5,20,1e-14], [2.5, 10,,1e-14], [-2, 69,0]);
 my $tests;
 $tests += $_->[1] foreach @pow;
 
-plan tests => 1 + $bits_in_uv + $tests;
+plan tests => 2 + $bits_in_uv + $tests;
+
+# This gave positive 27 before change #20167
+is((-3)**3, -27, "(negative int) ** (odd power) is negative");
 
 # Ought to be 32, 64, 36 or something like that.