https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117501
--- Comment #7 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The trunk branch has been updated by Marek Polacek <mpola...@gcc.gnu.org>: https://gcc.gnu.org/g:0d97700443b45b947eda40dac7cf4d0397770b87 commit r15-7306-g0d97700443b45b947eda40dac7cf4d0397770b87 Author: Marek Polacek <pola...@redhat.com> Date: Mon Jan 27 14:23:22 2025 -0500 c++: wrong-code with consteval constructor [PR117501] We've had a wrong-code problem since r14-4140, due to which we forget to initialize a variable. In consteval39.C, we evaluate struct QQQ q; <<cleanup_point <<< Unknown tree: expr_stmt QQQ::QQQ (&q, TARGET_EXPR <D.2687, <<< Unknown tree: aggr_init_expr 5 __ct_comp D.2687 (struct basic_string_view *) <<< Unknown tree: void_cst >>> (const char *) "" >>>>) >>>>>; into struct QQQ q; <<cleanup_point <<< Unknown tree: expr_stmt {.data={._M_len=42, ._M_str=0}} >>>>>; and then the useless expr_stmt is dropped on the floor, so q isn't initialized. As pre-r14-4140, we need to handle constructors specially. With this patch, we generate: struct QQQ q; <<cleanup_point <<< Unknown tree: expr_stmt q = {.data={._M_len=42, ._M_str=0}} >>>>>; initializing q properly. PR c++/117501 gcc/cp/ChangeLog: * cp-gimplify.cc (cp_build_init_expr_for_ctor): New. (cp_fold_immediate_r): Call it. (cp_fold): Break out code into cp_build_init_expr_for_ctor. gcc/testsuite/ChangeLog: * g++.dg/cpp2a/consteval39.C: New test. * g++.dg/cpp2a/consteval40.C: New test. Reviewed-by: Jason Merrill <ja...@redhat.com>
