* Makefile.in (loop-unroll.o): Add VARRAY_H dependency.
* loop-unroll.c: Include varray.h.
(struct var_to_expand, struct opt_info): Rename split_ivs_info to
opt_info and expand it to support variable expansion.
(analyze_insns_in_loop): Rename analyze_ivs_to_split and
expand it to support variable expansion.
(pt_info_start_duplication): Rename si_info_start_duplication.
(apply_opt_in_copies): Rename split_ivs_in_copies and add support
to the variable expansion optimization.
(free_opt_info): Rename free_si_info.
(analyze_insn_to_expand_var, referenced_in_one_insn_in_loop_p,
expand_var_during_unrolling, insert_var_expansion_initialization,
combine_var_copies_in_loop_exit, release_var_copies,
get_expansion): New functions.
(peel_loop_completely, unroll_loop_constant_iterations,
unroll_loop_runtime_iterations, peel_loop_simple,
unroll_loop_stupid): Change uses of struct si_info
to struct opt_info
and add uses of fvariable-expansion-in-unroller flag.
* params.def: Add parameter to restrict the number of expansions.
* params.h: (MAX_VARIABLE_EXPANSIONS): New define to restrict
the number of expansions.
* common.opt: (fvariable-expansion-in-unroller): New flag.
* doc/invoke.texi: (fvariable-expansion-in-unroller): Document.