https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101223
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
CC| |aldyh at gcc dot gnu.org,
| |amacleod at redhat dot com
Last reconfirmed| |2021-06-28
Ever confirmed|0 |1
Summary|[11/12 Regression] wrong |[11/12 Regression] evrp
|code at -O2 and above on |produces wrong code
|x86_64-linux-gnu |
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
The problem is in evrp.
Without evrp:
# f_10 = PHI <0(3), c.0_1(4)>
# g_11 = PHI <g_12(3), g_21(4)>
c = f_10;
.....
With VRP:
<bb 6> :
# g_11 = PHI <g_12(3), g_21(4)>
c = 0;
That is wrong.
c.0_1: int VARYING
_2: <unnamed-signed:1> VARYING
_3: <unnamed-signed:1> VARYING
_5: int [-1, 0]
_6: <unnamed-signed:1> VARYING
_8: int [-2147483647, 2]
d.2_9: int VARYING
g_11: int VARYING
g_12: int VARYING
g_15(D): UNDEFINED
e_18: int VARYING
g_21: int [-1, 0]
Huh:
Visiting PHI node: f_10 = PHI <0(3), c.0_1(4)>
Argument #0 (3 -> 6 executable)
0: int [0, 0]
Argument #1 (4 -> 6 executable)
c.0_1: int [c.0_1, c.0_1]
Meeting
int [0, 0]
and
int [c.0_1, c.0_1]
to
int VARYING
Intersecting
int VARYING
and
int VARYING
to
int VARYING
Visiting PHI node: g_11 = PHI <g_12(3), g_21(4)>
Argument #0 (3 -> 6 executable)
g_12: int [g_12, g_12]
Argument #1 (4 -> 6 executable)
g_21: int [-1, 0]
Meeting
int [g_12, g_12]
and
int [-1, 0]
to
int VARYING
Intersecting
int VARYING
and
int VARYING
to
int VARYING
Folding PHI node: f_10 = PHI <0(3), c.0_1(4)>
EVRP:hybrid: RVRP found singleton 0
Queued PHI for removal. Folds to: 0
Folding PHI node: g_11 = PHI <g_12(3), g_21(4)>
recomputation attempt on edge 4->6 for g_21 : Calculated :int VARYING
No folding possible
evrp visiting stmt c = f_10;
Folding statement: c = f_10;
EVRP:hybrid: RVRP found singleton 0
Folded into: c = 0;
We got int VARYING but still folded it to 0.
