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From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug ipa/98834] [10/11 Regression] Code path incorrectly determined to be unreachable Date: Tue, 26 Jan 2021 09:18:16 +0000 [thread overview] Message-ID: <bug-98834-4-hmkRITZOcY@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-98834-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98834 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Last reconfirmed| |2021-01-26 Keywords| |needs-bisection, wrong-code CC| |jamborm at gcc dot gnu.org, | |marxin at gcc dot gnu.org Ever confirmed|0 |1 Component|tree-optimization |ipa Target Milestone|--- |10.3 Priority|P3 |P2 Status|UNCONFIRMED |NEW --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- Confirmed, the __builtin_unreachable is introduced by inlining: Considering _S_multiplies.isra/23 with 12 size to be inlined into int main()/13 in t.C:54 Estimated badness is -inf, frequency 1.00. Badness calculation for int main()/13 -> _S_multiplies.isra/23 size growth -2, time 2.000000 unspec 10.000000 IPA hints: declared_inline big_speedup -inf: Growth -2 <= 0 Adjusted by hints -inf Accounting size:2.00, time:2.00 on predicate exec:(true) Introduced new external node (void __builtin_unreachable()/24). Processing frequency _S_multiplies.isra/23 Called by int main()/13 that is executed once Accounting size:-4.00, time:-13.00 on predicate exec:(true) t.C:54:62: optimized: Inlined _S_multiplies.isra/23 into int main()/13 which now has time 8.000000 and size 9, net change of -14. which points to IPA SRA. VRP then simplifies __builtin_constant_p seen as _12 = __builtin_constant_p (__xx_11); if (_12 != 0) goto <bb 4>; [100.00%] else goto <bb 3>; [0.00%] <bb 3> [count: 0]: __builtin_unreachable (); <bb 4> [local count: 1073741824]: MEM <int> [(struct _Tuple *)&D.2557] = 0; and uses conservatively false but that runs into __builtin_unreachable () ... The IPA inline transform ends us with _12 = __builtin_constant_p (__xx_11); if (_12 != 0) goto <bb 4>; [100.00%] else goto <bb 3>; [0.00%] <bb 3> [count: 0]: _13 = _16(D); __builtin_unreachable (); <bb 4> [local count: 1073741824]: # SR.30_15 = PHI <__y_10(2)> which eventually shows the reason (the unused argument?)
next prev parent reply other threads:[~2021-01-26 9:18 UTC|newest] Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-01-26 8:28 [Bug tree-optimization/98834] New: " kretz at kde dot org 2021-01-26 9:18 ` rguenth at gcc dot gnu.org [this message] 2021-01-26 9:20 ` [Bug ipa/98834] [10/11 Regression] " kretz at kde dot org 2021-01-26 9:29 ` kretz at kde dot org 2021-01-26 9:47 ` jakub at gcc dot gnu.org 2021-01-26 10:09 ` rguenther at suse dot de 2021-03-08 18:10 ` jamborm at gcc dot gnu.org 2021-03-15 12:40 ` rguenth at gcc dot gnu.org 2021-03-15 15:00 ` cvs-commit at gcc dot gnu.org 2021-03-15 15:02 ` rguenth at gcc dot gnu.org 2021-03-16 9:29 ` marxin at gcc dot gnu.org 2021-03-24 13:12 ` [Bug ipa/98834] [10 " rguenth at gcc dot gnu.org 2021-03-24 14:26 ` cvs-commit at gcc dot gnu.org 2021-03-24 14:27 ` rguenth at gcc dot gnu.org
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