https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121586
Bug ID: 121586
Summary: aliased built-in function generated code calling
itself
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: bpar at skl dot vc
Target Milestone: ---
For an embedded project I wrote a simple version of clib's "memset". When I
compiled with -O2, gcc produced weird code including a recursive call.
This bug appears to have stated with v10 and continues up to v15 (I didn't try
16).
I only tried arm 32 bit architectures but I think it happens in aarch64 as
well.
It looks like gcc "recognizes" that the code is doing a memset and then tried
to call glib's memset. But the function is called memset, so this is
recursive.
-O1 doesn't have the problem. and adding -fnobuiltin also causes the problem
to go away.
#include <stdint.h>
#include <stddef.h>
void *memset(void *s, int c, size_t n)
{
uint8_t *p = (uint8_t *)s;
while (n > 0) {
*p++ = c;
n--;
}
return s;
}
kinda dumb, yes. but I think it should recognize that it's trying to optimize
by calling the function it's optimizing.
