https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98469
--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:606f2af1973d5c83877d327cb5adef97c4243a73 commit r11-6477-g606f2af1973d5c83877d327cb5adef97c4243a73 Author: Jakub Jelinek <ja...@redhat.com> Date: Tue Jan 5 17:17:57 2021 +0100 c++: Fix ICE with __builtin_bit_cast [PR98469] On the following testcase we ICE during constexpr evaluation (for warnings), because the IL has ADDR_EXPR of BIT_CAST_EXPR and ADDR_EXPR case asserts the result is not a CONSTRUCTOR. The patch punts on lval BIT_CAST_EXPR folding. > This change is OK, but part of the problem is that we're trying to do > overload resolution for an S copy/move constructor, which we shouldn't be > because bit_cast is a prvalue, so in C++17 and up we should use it to > directly initialize the target without any implied constructor call. This version therefore wraps it into a TARGET_EXPR then, it alone fixes the bug, but I've kept the constexpr.c change too. 2021-01-05 Jakub Jelinek <ja...@redhat.com> PR c++/98469 * constexpr.c (cxx_eval_constant_expression) <case BIT_CAST_EXPR>: Punt if lval is true. * semantics.c (cp_build_bit_cast): Call get_target_expr_sfinae on the result if it has a class type. * g++.dg/cpp2a/bit-cast8.C: New test. * g++.dg/cpp2a/bit-cast9.C: New test.