https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108115
Bug ID: 108115
Summary: spurious pointer used after realloc warning
Product: gcc
Version: 12.1.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: t...@develop-help.com
Target Milestone: ---
Created attachment 54097
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=54097&action=edit
Code that demonstrates the warning
gcc 12.0.1 produces a spurious warning when an access to an integer copy of a
pointer is accessed within an unrelated runtime conditional.
With the attachment:
$ /opt/gcc-12.1.0/bin/gcc -c -std=c99 -O2 -Wall -Wextra gcc-20507-simple.c
gcc-20507-simple.c: In function ‘my_realloc’:
gcc-20507-simple.c:13:15: warning: pointer ‘p’ may be used after ‘realloc’
[-Wuse-after-free]
13 | uintptr_t u = (uintptr_t)p;
| ^
gcc-20507-simple.c:15:18: note: call to ‘realloc’ here
15 | void *newp = realloc(p, newsz);
| ^~~~~~~~~~~~~~~~~
$ /opt/gcc-12.1.0/bin/gcc -c -std=c99 -O2 -Wall -Wextra -DDEBUG=1
gcc-20507-simple.c
(no diagnostics)
Note that p is not used after the realloc() in either case.
