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From: "symbioticfemale at cumallover dot me" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug c/113769] New: GCC fails to warn of integer being used uninitialized Date: Mon, 05 Feb 2024 14:07:17 +0000 [thread overview] Message-ID: <bug-113769-4@http.gcc.gnu.org/bugzilla/> (raw) https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113769 Bug ID: 113769 Summary: GCC fails to warn of integer being used uninitialized Product: gcc Version: 13.2.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c Assignee: unassigned at gcc dot gnu.org Reporter: symbioticfemale at cumallover dot me Target Milestone: --- // The "used uninitialized" warning is not produced on both GCC and Tiny Compiler. Clang recognizes the error. (-Wall on all compilers). See line comments for further explanation. The latest version of GCC I've tested with is 13.2.1. // Version 1: With printf #include <stdio.h> #include <stdint.h> #include <pthread.h> pthread_rwlock_t necessary_lock = PTHREAD_RWLOCK_INITIALIZER; void do_nothing(const void *value); void do_nothing(const void *value) { printf("%p\n",value); // do anything on value other than (void) value } int main(void) { pthread_rwlock_rdlock(&necessary_lock); pthread_rwlock_unlock(&necessary_lock); // Fun fact: remove either the pthread_rwlock_rdlock + pthread_rwlock_unlock, or the printf in do_nothing, and GCC catches the lack of initialization uint32_t pos; pos += 1; do_nothing(&pos); printf("%u\n",pos); } // Version 2: Without printf #include <stdio.h> #include <stdint.h> #include <pthread.h> pthread_rwlock_t necessary_lock = PTHREAD_RWLOCK_INITIALIZER; void do_nothing(const void *value); void do_nothing(const void *value) { (void) value; } int main(void) { pthread_rwlock_rdlock(&necessary_lock); pthread_rwlock_unlock(&necessary_lock); // Fun fact: remove either the pthread_rwlock_rdlock + pthread_rwlock_unlock, or the do_nothing function call, and GCC catches the lack of initialization. Add a printf after do_nothing and GCC will also catch it. uint32_t pos; pos += 1; do_nothing(&pos); }
next reply other threads:[~2024-02-05 14:07 UTC|newest] Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top 2024-02-05 14:07 symbioticfemale at cumallover dot me [this message] 2024-02-05 14:22 ` [Bug c/113769] " symbioticfemale at cumallover dot me 2024-02-05 14:25 ` redi at gcc dot gnu.org 2024-02-05 16:56 ` [Bug tree-optimization/113769] " pinskia at gcc dot gnu.org
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