https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67971
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |ASSIGNED
Last reconfirmed| |2015-10-15
Assignee|unassigned at gcc dot gnu.org |rguenth at gcc dot
gnu.org
Ever confirmed|0 |1
--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
VRP jump-threads this into sth PRE then can transform to
<bb 2>:
if (cond_3(D) != 0)
goto <bb 3>;
else
goto <bb 4>;
<bb 3>:
z1_5 = __builtin_cos (x_4(D));
goto <bb 5>;
<bb 4>:
z1_7 = __builtin_cos (y_6(D));
<bb 5>:
# iftmp.0_2 = PHI <y_6(D)(4), x_4(D)(3)>
# z1_13 = PHI <z1_7(4), z1_5(3)>
# prephitmp_1 = PHI <z1_7(4), z1_5(3)>
# RANGE [0, 1]
_9 = prephitmp_1 == z1_13;
# RANGE [0, 1] NONZERO 1
_10 = (int) _9;
return _10;
leaving the followup missed equivalency for the inserted PHI.
but then somehow DOM running later CSEing z1_13 and prephitmp_1 fails
to fold the comparison and we end up with
_9 = z1_13 == z1_13;
which even forwprop doesn't simplify (even though it is supposed to fold
all stmts). We do have
(simplify
(eq @0 @0)
(if (! FLOAT_TYPE_P (TREE_TYPE (@0))
|| ! HONOR_NANS (TYPE_MODE (TREE_TYPE (@0))))
{ constant_boolean_node (true, type); }))
but for some reason it doesn't trigger.
Investigating.
