PR c/65179
* c-common.c (c_fully_fold_internal): Warn when left shifting a
negative value.
* c.opt (Wshift-negative-value): New option.
* c-opts.c (c_common_post_options): Set warn_shift_negative_value
when -Wextra and C99/C++11 mode.
* c-typeck.c (build_binary_op): Warn when left shifting a negative
value.
* typeck.c (cp_build_binary_op): Warn when left shifting a negative
value.
* doc/invoke.texi: Document -Wshift-negative-value.
* c-c++-common/Wshift-negative-value-1.c: New test.
* testsuite/c-c++-common/Wshift-negative-value-2.c: New test.
* testsuite/c-c++-common/Wshift-negative-value-3.c: New test.
* testsuite/c-c++-common/Wshift-negative-value-4.c: New test.
* testsuite/c-c++-common/Wshift-negative-value-5.c: New test.
* testsuite/c-c++-common/Wshift-negative-value-6.c: New test.
* testsuite/gcc.dg/c90-left-shift-1.c: New test.
* testsuite/gcc.dg/c99-const-expr-7.c: Add dg-error.
* testsuite/gcc.dg/c99-left-shift-1.c: New test.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@222889
138bc75d-0d04-0410-961f-
82ee72b054a4