PATCH for reorg.c: Avoid side_effects_p when "opposite arithmetic".

[Jeffrey A Law]

 In message < 200004121605.SAA19945@ignucius.axis.se >you write:
  > The patch is bootstrapped and checked with gcc_ss_20000327 on
  > sparc-sun-solaris2.6 with no (new) regressions.
  > 
  > Ok to install patch and testcase?
  > Ok to install (patch only) on 2.95 branch?
The patch and testcase are fine for hte development tree.

I don't think this is important enough to fix in the 2.95 tree.

jeff