https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90710
--- Comment #4 from Martin Sebor <msebor at gcc dot gnu.org> ---
Here's a smaller test case showing both the problem (first gcc invocation) and
how it can be avoided (second invocation):
$ (set -x && cat pr90710.c && gcc -Og -S -Wall pr90710.c && gcc -Dint=long -Og
-S -Wall pr90710.c)
+ cat pr90710.c
static inline int f (int x, int *p)
{
if (x == 0)
return 0;
*p = x;
return 1;
}
volatile int z;
void g (int x)
{
int b, a = f (x, &b);
if (a)
z = b;
if (__builtin_expect (a, 1))
z = b;
}
+ gcc -Og -S -Wall pr90710.c
pr90710.c: In function ‘g’:
pr90710.c:20:7: warning: ‘b’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
20 | z = b;
| ~~^~~
pr90710.c:14:7: note: ‘b’ was declared here
14 | int b, a = f (x, &b);
| ^
+ gcc -Dint=long -Og -S -Wall pr90710.c
