https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102075
Bug ID: 102075
Summary: fill_always_executed_in_1 incomplete computation
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: luoxhu at gcc dot gnu.org
Target Milestone: ---
ALWAYS_EXECUTED_IN is not computed completely for nested loops. Current design
will exit if an inner loop doesn't dominate outer loop's latch or exit after
exiting from inner loop, which caused early return from outer loop, then ALWAYS
EXECUTED blocks after inner loops are skipped.
For example, x->k should be move out of outer loop but doesn't.
struct X { int i; int j; int k;};
void foo(struct X *x, int n, int l)
{
for (int j = 0; j < l; j++)
{
for (int i = 0; i < n; ++i)
{
int *p = &x->j;
int tem = *p;
x->j += tem * i;
}
int *r = &x->k;
int tem2 = *r;
x->k += tem2 * j;
}
}
Discussion lists:
https://gcc.gnu.org/pipermail/gcc-patches/2021-August/577444.html
