Incorrect results from numerical library when using -ftree-ter

[Szabolcs Horvát]

Hello,

I am using the Triangle library
<http://www.cs.cmu.edu/~quake/triangle.html> to generate Delaunay
triangulations of a large number of points.  When I compile this
library using the -ftree-ter optimization option only, the library
gives me incorrect results for certain inputs.  The -ftree-ter  option
is enabled by optimization level -O1 or higher, which also cause the
library to return incorrect results.

Question:  Does this indicate that there is a bug in gcc or is it more
likely that there's a problem in how the library is written?

Unfortunately I am not familiar with the code of Triangle, I just
compile it and use it.

I tried this with gcc 4.6.3 on Ubuntu and gcc 4.7.0 on Windows (from
<http://nuwen.net/mingw.html>), both 32-bit.

Szabolcs