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From: "marxin at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org> To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/96722] [8/9/10/11 Regression] Clobbers on NULL since r8-1519 Date: Thu, 20 Aug 2020 13:59:25 +0000 [thread overview] Message-ID: <bug-96722-4-rKKLYXglDW@http.gcc.gnu.org/bugzilla/> (raw) In-Reply-To: <bug-96722-4@http.gcc.gnu.org/bugzilla/> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96722 Martin Liška <marxin at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Assignee|marxin at gcc dot gnu.org |unassigned at gcc dot gnu.org Status|ASSIGNED |NEW --- Comment #2 from Martin Liška <marxin at gcc dot gnu.org> --- So the problematic transformation happens in einline: BEFORE: void foo(S*) (struct S * a) { <bb 2> [0.00%] [count: INV]: if (a_2(D) != 0B) goto <bb 4>; [0.00%] [count: INV] else goto <bb 3>; [0.00%] [count: INV] <bb 3> [100.00%] [count: INV]: MEM[(struct &)a_2(D)] ={v} {CLOBBER}; <bb 4> [0.00%] [count: INV]: return; } after: void foo(S*) (struct S * a) { <bb 2> [0.00%] [count: INV]: if (a_2(D) != 0B) goto <bb 3>; [0.00%] [count: INV] else goto <bb 4>; [0.00%] [count: INV] <bb 3> [0.00%] [count: INV]: // predicted unlikely by early return (on trees) predictor. goto <bb 5>; [0.00%] [count: INV] <bb 4> [100.00%] [count: INV]: MEM[(struct &)a_2(D)] ={v} {CLOBBER}; <bb 5> [0.00%] [count: INV]: return; } So as seen, the CFG is more complex as there's an extra GIMPLE_PREDICT. main then inlines to: Scope blocks after cleanups: { Scope block #0 { Scope block #7 ../pr96722.C:8 Originating from : extern void S (struct S *, int); } { Scope block #8 ../pr96722.C:14 Originating from : extern void S (struct S *, int); } } int main() () { int _5; <bb 2> [100.00%] [count: INV]: _5 = 0; return _5; } No longer having address taken: s Scope blocks after cleanups: { Scope block #0 { Scope block #7 ../pr96722.C:8 Originating from : extern void S (struct S *, int); { Scope block #8 Originating from :#0 } } { Scope block #9 ../pr96722.C:14 Originating from : extern void S (struct S *, int); } } int main() () { int _5; <bb 2> [100.00%] [count: INV]: MEM[(struct &)0B] ={v} {CLOBBER}; _5 = 0; return _5; } So I bet it's hidden in a CFG cleanup where it somehow removes the clobber? I guess it was latent before my revision..
next prev parent reply other threads:[~2020-08-20 13:59 UTC|newest] Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-08-20 9:30 [Bug tree-optimization/96722] New: " jakub at gcc dot gnu.org 2020-08-20 9:30 ` [Bug tree-optimization/96722] " jakub at gcc dot gnu.org 2020-08-20 9:39 ` marxin at gcc dot gnu.org 2020-08-20 13:59 ` marxin at gcc dot gnu.org [this message] 2020-08-24 11:30 ` jakub at gcc dot gnu.org 2020-08-24 12:08 ` rguenther at suse dot de 2020-08-24 13:07 ` jakub at gcc dot gnu.org 2020-08-24 13:49 ` rguenth at gcc dot gnu.org 2020-08-25 11:50 ` cvs-commit at gcc dot gnu.org 2020-08-25 17:45 ` cvs-commit at gcc dot gnu.org 2020-08-25 18:26 ` jakub at gcc dot gnu.org 2020-09-01 8:33 ` rguenth at gcc dot gnu.org 2020-09-01 10:56 ` [Bug tree-optimization/96722] [8/9 " jakub at gcc dot gnu.org 2020-09-16 19:23 ` cvs-commit at gcc dot gnu.org 2020-09-17 17:58 ` jakub at gcc dot gnu.org
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