https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90036
Richard Biener <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |amacleod at redhat dot com
Depends on| |85316
--- Comment #19 from Richard Biener <rguenth at gcc dot gnu.org> ---
For the comment#8 testcase the thing is that thread1 isolated the path with the
unreachable edge (it actually threaded the _3 == 0 -> ownvptr == 0 path). But
the backwards threader does not seem to try simplify the isolated paths.
And even VRP2 cannot simplify that (that would be too late, strlen1 diagnoses).
Andrew?
<bb 2> [local count: 1073741824]:
_1 = vptr_14(D) == 0;
_2 = ownvptr_15(D) != 0;
_3 = _1 | _2;
if (_3 != 0)
goto <bb 4>; [67.00%]
else
goto <bb 3>; [33.00%]
<bb 4> [local count: 719407024]:
if (vptr_14(D) != 0)
goto <bb 5>; [25.37%]
else
goto <bb 9>; [74.63%]
<bb 5> [local count: 182536112]:
if (_2 != 0)
goto <bb 7>; [80.00%]
else
goto <bb 6>; [20.00%]
from _3 != 0 && vptr_14(D) != 0 follows _2 != 0. Why do we not see this?
Referenced Bugs:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85316
[Bug 85316] [meta-bug] VRP range propagation missed cases
