Fix exponentiation operation to avoid overflow.

The exponentation implementation unnecessarily multiplied the
result with itself at the end if the exponent was an even number.
This led to overflow if result*result > high(int).

1 files changed, 3 insertions, 1 deletions

diff --git a/lib/pure/math.nim b/lib/pure/math.nim
index 821ab738b..8d95ea9c0 100644
--- a/lib/pure/math.nim
+++ b/lib/pure/math.nim
@@ -427,10 +427,12 @@ proc `^`*[T](x, y: T): T =
   var (x, y) = (x, y)
   result = 1
 
-  while y != 0:
+  while true:
     if (y and 1) != 0:
       result *= x
     y = y shr 1
+    if y == 0:
+      break
     x *= x
 
 proc gcd*[T](x, y: T): T =