Replace exact_log2(x & -x) in favor of more direct computation.
* toplev.h (ctz_hwi, clz_hwi, ffs_hwi): New.
(floor_log2): Use clz_hwi.
(exact_log2): Use ctz_hwi.
* toplev.c (ctz_hwi, clz_hwi, ffs_hwi): New.
* builtins.c (fold_builtin_bitop): Use them.
* simplify-rtx.c (simplify_const_unary_operation): Likewise.
* combine.c (get_pos_from_mask): Use ctz_hwi.
* double-int.c (double_int_ctz): Likewise.
* explow.c (force_reg): Likewise.
* tree.h (SET_DECL_OFFSET_ALIGN): Use ffs_hwi.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@162920
138bc75d-0d04-0410-961f-
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