https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63569
Bug ID: 63569
Summary: [5.0 Regression] Wrong code with volatile and ICF
Product: gcc
Version: 5.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: pinskia at gcc dot gnu.org
Take:
static int f(int t, int *a) __attribute__((noinline));
static int g(int t, volatile int *a) __attribute__((noinline));
static int g(int t, volatile int *a)
{
int i;
int tt = 0;
for(i=0;i<t;i++)
tt += *a;
return tt;
}
static int f(int t, int *a)
{
int i;
int tt = 0;
for(i=0;i<t;i++)
tt += *a;
return tt;
}
int h(int t, int *a)
{
return f(t, a) + g(t, a);
}
--- CUT ---
The order of f and g are important.
The .icf dump has:
Semantic equality hit:f->g
Assembler symbol names:f->g
Which is incorrect as they are not semantic equivalent as one you can load from
a only once while the other you need to load a each time through the loop.
