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[Bug tree-optimization/62217] Extra iteration peeled during cunroll. Makes VRP warn.
- From: "pinskia at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: Fri, 22 Aug 2014 04:41:12 +0000
- Subject: [Bug tree-optimization/62217] Extra iteration peeled during cunroll. Makes VRP warn.
- Auto-submitted: auto-generated
- References: <bug-62217-4 at http dot gcc dot gnu dot org/bugzilla/>
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=62217
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Actually it is a bad interaction between DOM and complete unrolling.
<bb 20>:
# i_14 = PHI <i_36(19)>
if (i_14 == b_6(D))
goto <bb 21>;
else
goto <bb 22>;
<bb 21>:
g_x[b_6(D)] = *x1_7(D);
i_11 = i_14 + 1;
goto <bb 3>;
<bb 22>:
__builtin_unreachable ();
--- CUT ---
Basic Block 21 should have been a __builtin_unreachable (); also.
BB21 was bb5 after dom.
BB5 was changed all the way back in dom to:
<bb 5>:
g_x[b_6(D)] = *x1_7(D);
goto <bb 7>;
It was before DOM:
<bb 5>:
g_x[i_14] = *x2_9(D);