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* [Bug tree-optimization/79119] absolute value of a pointer difference can be assumed to be less than or equal to PTRDIFF_MAX [not found] <bug-79119-4@http.gcc.gnu.org/bugzilla/> @ 2023-04-27 22:31 ` pinskia at gcc dot gnu.org 2023-05-02 0:15 ` pinskia at gcc dot gnu.org 2023-05-06 20:20 ` pinskia at gcc dot gnu.org 2 siblings, 0 replies; 3+ messages in thread From: pinskia at gcc dot gnu.org @ 2023-04-27 22:31 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79119 --- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> --- So a couple of things need to happen really: optimized now: if (p_10 < q_12) goto <bb 3>; [50.00%] else goto <bb 4>; [50.00%] <bb 3> [local count: 536870913]: _3 = _22 - _21; _4 = _3 /[ex] 4; iftmp.0_14 = (long unsigned int) _4; goto <bb 5>; [100.00%] <bb 4> [local count: 536870913]: _5 = _21 - _22; _6 = _5 /[ex] 4; iftmp.0_13 = (long unsigned int) _6; <bb 5> [local count: 1073741824]: # iftmp.0_7 = PHI <iftmp.0_14(3), iftmp.0_13(4)> I have a patch which is able to move the cast out of the PHI (will be posting it today or tomorrow). The next thing is we need to move the /[ext] 4 out of the PHI, I have not extended PHIOPT to do that just yet (just extended it to handle unary operations though). And then we have to see the abs but with _22/_21 being unrelated to p_10/q_12 except with a cast, it might be hard. I am looking into a patch for the case where if _22/_21 was in the conditional. ^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug tree-optimization/79119] absolute value of a pointer difference can be assumed to be less than or equal to PTRDIFF_MAX [not found] <bug-79119-4@http.gcc.gnu.org/bugzilla/> 2023-04-27 22:31 ` [Bug tree-optimization/79119] absolute value of a pointer difference can be assumed to be less than or equal to PTRDIFF_MAX pinskia at gcc dot gnu.org @ 2023-05-02 0:15 ` pinskia at gcc dot gnu.org 2023-05-06 20:20 ` pinskia at gcc dot gnu.org 2 siblings, 0 replies; 3+ messages in thread From: pinskia at gcc dot gnu.org @ 2023-05-02 0:15 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79119 --- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> --- Hmm: # RANGE [irange] long unsigned int [0, 2305843009213693951][16140901064495857664, +INF] iftmp.0_7 = (long unsigned intD.10) _19; if (iftmp.0_7 > 2305843009213693951) So that is _19 < 0 If I read this correctly. The only reason why it was not converted is because of the /4 that was before. So we have a hole in the range. ^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug tree-optimization/79119] absolute value of a pointer difference can be assumed to be less than or equal to PTRDIFF_MAX [not found] <bug-79119-4@http.gcc.gnu.org/bugzilla/> 2023-04-27 22:31 ` [Bug tree-optimization/79119] absolute value of a pointer difference can be assumed to be less than or equal to PTRDIFF_MAX pinskia at gcc dot gnu.org 2023-05-02 0:15 ` pinskia at gcc dot gnu.org @ 2023-05-06 20:20 ` pinskia at gcc dot gnu.org 2 siblings, 0 replies; 3+ messages in thread From: pinskia at gcc dot gnu.org @ 2023-05-06 20:20 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79119 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- See Also| |https://gcc.gnu.org/bugzill | |a/show_bug.cgi?id=94274 --- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> --- (In reply to Andrew Pinski from comment #3) > So a couple of things need to happen really: > optimized now: > if (p_10 < q_12) > goto <bb 3>; [50.00%] > else > goto <bb 4>; [50.00%] > > <bb 3> [local count: 536870913]: > _3 = _22 - _21; > _4 = _3 /[ex] 4; > iftmp.0_14 = (long unsigned int) _4; > goto <bb 5>; [100.00%] > > <bb 4> [local count: 536870913]: > _5 = _21 - _22; > _6 = _5 /[ex] 4; > iftmp.0_13 = (long unsigned int) _6; > > <bb 5> [local count: 1073741824]: > # iftmp.0_7 = PHI <iftmp.0_14(3), iftmp.0_13(4)> Most of that is PR 94274 . ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2023-05-06 20:20 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- [not found] <bug-79119-4@http.gcc.gnu.org/bugzilla/> 2023-04-27 22:31 ` [Bug tree-optimization/79119] absolute value of a pointer difference can be assumed to be less than or equal to PTRDIFF_MAX pinskia at gcc dot gnu.org 2023-05-02 0:15 ` pinskia at gcc dot gnu.org 2023-05-06 20:20 ` pinskia at gcc dot gnu.org
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