https://gcc.gnu.org/bugzilla/show_bug.cgi?id=52119
--- Comment #16 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Fixed by r225998
PR c++/55095
* c-common.c (c_fully_fold_internal): Warn about left shift
overflows.
Use EXPR_LOC_OR_LOC.
(maybe_warn_shift_overflow): New function.
* c-common.h (maybe_warn_shift_overflow): Declare.
* c-opts.c (c_common_post_options): Set warn_shift_overflow.
* c.opt (Wshift-overflow): New option.
* c-typeck.c (digest_init): Pass OPT_Wpedantic to pedwarn_init.
(build_binary_op): Warn about left shift overflows.
* typeck.c (cp_build_binary_op): Warn about left shift overflows.
* doc/invoke.texi: Document -Wshift-overflow and -Wshift-overflow=.
