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 (file)
--- 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 (file)
--- 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.