https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104633
--- Comment #6 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:c8cb5098c7854a1ed07e85c6165ef0c348d6df1d commit r12-7358-gc8cb5098c7854a1ed07e85c6165ef0c348d6df1d Author: Jakub Jelinek <ja...@redhat.com> Date: Wed Feb 23 12:03:55 2022 +0100 warn-recursion: Don't warn for __builtin_calls in gnu_inline extern inline functions [PR104633] The first two testcases show different ways how e.g. the glibc _FORTIFY_SOURCE wrappers are implemented, and on Winfinite-recursion-3.c the new -Winfinite-recursion warning emits a false positive warning. It is a false positive because when a builtin with 2 names is called through the __builtin_ name (but not all builtins have a name prefixed exactly like that) from extern inline function with gnu_inline semantics, it doesn't mean the compiler will ever attempt to use the user inline wrapper for the call, the __builtin_ just does what the builtin function is expected to do and either expands into some compiler generated code, or if the compiler decides to emit a call it will use an actual definition of the function, but that is not the extern inline gnu_inline function which is never emitted out of line. Compared to that, in Winfinite-recursion-5.c the extern inline gnu_inline wrapper calls the builtin by the same name as the function's name and in that case it is infinite recursion, we actuall try to inline the recursive call and also error because the recursion is infinite during inlining; without always_inline we wouldn't error but it is still infinite recursion, the user has no control on how many recursive calls we actually inline. 2022-02-22 Jakub Jelinek <ja...@redhat.com> PR c/104633 * gimple-warn-recursion.cc (pass_warn_recursion::find_function_exit): Don't warn about calls to corresponding builtin from extern inline gnu_inline wrappers. * gcc.dg/Winfinite-recursion-3.c: New test. * gcc.dg/Winfinite-recursion-4.c: New test. * gcc.dg/Winfinite-recursion-5.c: New test.
