re PR tree-optimization/18463 (suboptimal use of fancy x86 addressing modes)
PR tree-optimization/18463
* tree-chrec.c (chrec_convert): Return fold_converted chrec if
converting it directly is not possible.
(chrec_convert_aggressive): New function.
* tree-chrec.h (chrec_convert_aggressive): Declare.
* tree-scalar-evolution.c (instantiate_parameters_1, resolve_mixers):
Fold chrec conversions aggressively if asked to.
(instantiate_parameters): Modified because of changes in
instantiate_parameters_1.