https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84607
Bug ID: 84607
Summary: Side effects discarded in address computation inside
'if'
Product: gcc
Version: 7.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: stephen.dolan at cl dot cam.ac.uk
Target Milestone: ---
This program should print "hello" and "goodbye", but only prints "goodbye":
#include <stdio.h>
int a[10];
int foo() {
puts("hello");
return 0;
}
int main() {
if (&a[foo()])
puts("goodbye");
return 0;
}
I tested locally with gcc 7.2.0 (Debian 7.2.0-19). I also tried the program
with the various gcc versions on godbolt.org, and the problem seems to exist in
all versions since gcc 6 (gcc 5.5 is unaffected). The presence or absence of
-O3 doesn't seem to make a difference.
