https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88680
--- Comment #3 from David Malcolm <dmalcolm at gcc dot gnu.org> --- Author: dmalcolm Date: Sat Feb 16 16:17:17 2019 New Revision: 268961 URL: https://gcc.gnu.org/viewcvs?rev=268961&root=gcc&view=rev Log: Fix excess warnings from -Wtype-limits with location wrappers (PR c++/88680) PR c++/88680 reports excess warnings from -Wtype-limits after the C++ FE's use of location wrappers was extended in r267272 for cases such as: const unsigned n = 8; static_assert (n >= 0 && n % 2 == 0, ""); t.C:3:18: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits] 3 | static_assert (n >= 0 && n % 2 == 0, ""); | ~~^~~~ The root cause is that the location wrapper around "n" breaks the suppression of the warning for the "if OP0 is a constant that is >= 0" case. This patch fixes it by calling fold_for_warn on OP0, extracting the constant. gcc/c-family/ChangeLog: PR c++/88680 * c-common.c (shorten_compare): Call fold_for_warn on op0 when implementing -Wtype-limits. gcc/testsuite/ChangeLog: PR c++/88680 * g++.dg/wrappers/pr88680.C: New test. Added: trunk/gcc/testsuite/g++.dg/wrappers/pr88680.C Modified: trunk/gcc/c-family/ChangeLog trunk/gcc/c-family/c-common.c trunk/gcc/testsuite/ChangeLog
