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/* { dg-do compile } */
/* { dg-options "-O1 -fstrict-aliasing -fdump-tree-optimized" } */
/* This is a small variant of pr110539-3.c using -O1 -fstrict-aliasing
rather than -O2. Just to show VRP and PRE is not needed to optimize
the call to foo away. */
void foo(void);
static int a, c = 1;
static short b;
static int *d = &c, *e = &a;
static int **f = &d;
void __assert_fail() __attribute__((__noreturn__));
static void g(int h) {
if (*d)
;
else {
if (e) __assert_fail();
if (a) {
__builtin_unreachable();
} else
__assert_fail();
}
if (((h!=0) == h) + b) *f = 0;
}
int main() {
int i = 0 != 10 & a;
g(i);
*e = 9;
e = 0;
if (d == 0)
;
else
foo();
;
}
/* The call to foo should be optimized away. */
/* The missed optimization at -O1 here was:
int b = a & 1;
int c = b != 0;
int d = c == b;
not being optimized to 1 early enough, it is done in vrp2 but
that is too late.
In phiopt2 we got:
_17 = i_7 != 0;
_12 = (int) _17;
if (i_7 == _12)
goto <bb 9>; [50.00%]
else
goto <bb 10>; [50.00%]
<bb 9> [local count: 268435456]:
d = 0B;
<bb 10> [local count: 536870913]:
e.1_3 = e;
*e.1_3 = 9;
e = 0B;
d.2_4 = d;
if (d.2_4 == 0B)
The first if is not optimized before, until vrp2 which is
too late as there are no passes which will then find the
load of d in `d.2_4 = d;` was `0B` after vrp2.
Now in forwprop3 (after phiopt2), we optimize:
_17 = i_7 != 0;
_12 = (int) _17;
if (i_7 == _12)
into just:
_t = (unsigned)i_7;
if (_t <= 1)
And then during ccp3, that is optimized away and that is optimized
early enough now that the load `d.2_4 = d;` is optimizd to just
`d.2_4 = 0B;`
*/
/* { dg-final { scan-tree-dump-not "foo \\(\\)" "optimized"} } */
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