Move constant bitop and bswap folds to fold-const-call.c
The only folds left in builtins.c were for constants, so we can remove
the builtins.c handling entirely.
Tested on x86_64-linux-gnu, aarch64-linux-gnu and arm-linux-gnueabi.
gcc/
* builtins.c (fold_builtin_bitop, fold_builtin_bswap): Delete.
(fold_builtin_1): Don't call them.
* fold-const-call.c: Include tm.h.
(fold_const_call_ss): New variant for integer-to-integer folds.
(fold_const_call): Call it.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@229921 138bc75d-0d04-0410-961f-82ee72b054a4