https://gcc.gnu.org/bugzilla/show_bug.cgi?id=70195
Bug ID: 70195
Summary: GCC silently drops erroneous assignments in flexible
arrays
Product: gcc
Version: 5.3.1
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: frederic.petrot at gmail dot com
Target Milestone: ---
Even though using flexible arrays and returning them through functions may not
be the wisest thing to do, ...
The following code compiles without warnings:
typedef struct w {
int x;
int y[];
} w;
w xy(int z)
{
w v;
v.x = 3;
v.y[0]=z;
v.y[2]=z+1;
v.y[11]=z+22;
return v;
}
Interestingly enough, but as expected indeed, it produces different behaviors
at asm level depending on the optimization level. Without optimization, it
accesses the caller stack to mess it up, with optimization on, it simply sets
the x field in the caller stack (mips) or returns it (x86).
