+ Implemented target-independent optimization of signed "mod 2**N" as
  "sign:=left sar sizeof(left)*8-1; result:=(((left xor sign)-sign) and 2**N-1) xor sign)-sign;"
  This solution yields larger code than one suggested by Mantis #21152, however its speed on i386 is approximately the same, and it is also suitable for all operand sizes, all powers of two and all targets.


git-svn-id: http://svn.freepascal.org/svn/fpc/trunk@27891 3ad0048d-3df7-0310-abae-a5850022a9f2