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* [Bug tree-optimization/42436] VRP should mark non-trapping integer divisions [not found] <bug-42436-4@http.gcc.gnu.org/bugzilla/> @ 2022-01-12 16:14 ` amacleod at redhat dot com 2022-01-13 7:13 ` rguenth at gcc dot gnu.org 1 sibling, 0 replies; 3+ messages in thread From: amacleod at redhat dot com @ 2022-01-12 16:14 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42436 --- Comment #3 from Andrew Macleod <amacleod at redhat dot com> --- What needs to be done here? anything? Looking at VRP1, there is only a single divide left at that point: countm1.6_54 = _12 / _13; and VRP1 is setting the global range of _13 to: _13: unsigned int [2, 2147483647] So at least from that point on, it is trivial to determine the divide is non-trapping even using the global ranges. ^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug tree-optimization/42436] VRP should mark non-trapping integer divisions [not found] <bug-42436-4@http.gcc.gnu.org/bugzilla/> 2022-01-12 16:14 ` [Bug tree-optimization/42436] VRP should mark non-trapping integer divisions amacleod at redhat dot com @ 2022-01-13 7:13 ` rguenth at gcc dot gnu.org 1 sibling, 0 replies; 3+ messages in thread From: rguenth at gcc dot gnu.org @ 2022-01-13 7:13 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=42436 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Resolution|--- |FIXED Status|NEW |RESOLVED --- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> --- I think this was trying to cover things like if (d != 0) tem = a / d; where the non-zero range of d on the division cannot be put in global ranges for its SSA name since that would be incorrect for uses not guarded by the condition. So it would ask for a new flag on GIMPLE statements to mark the division not trapping (like we have TREE_THIS_NOTRAP). Transforms like PRE or LIM that do code motion of course have to be careful to not move the stmt outside of the condition that made it not trapping - something which would be as hard to guarantee as computing the non-trappingness in the first place. So yes, the case that made me file this bug is fixed with global ranges. Let's close this bug since it's quite unspecific. ^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug tree-optimization/42436] New: VRP should mark non-trapping integer divisions @ 2009-12-19 19:41 rguenth at gcc dot gnu dot org 2009-12-19 19:42 ` [Bug tree-optimization/42436] " rguenth at gcc dot gnu dot org 0 siblings, 1 reply; 3+ messages in thread From: rguenth at gcc dot gnu dot org @ 2009-12-19 19:41 UTC (permalink / raw) To: gcc-bugs In PR42108 a division is found to be non-trapping by VRP but neither PRE nor LIM can make use of that information (well, because VRP doesn't mark the divisions in any meaningful way). -- Summary: VRP should mark non-trapping integer divisions Product: gcc Version: 4.5.0 Status: UNCONFIRMED Keywords: missed-optimization Severity: enhancement Priority: P3 Component: tree-optimization AssignedTo: unassigned at gcc dot gnu dot org ReportedBy: rguenth at gcc dot gnu dot org OtherBugsDependingO 42108 nThis: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42436 ^ permalink raw reply [flat|nested] 3+ messages in thread
* [Bug tree-optimization/42436] VRP should mark non-trapping integer divisions 2009-12-19 19:41 [Bug tree-optimization/42436] New: " rguenth at gcc dot gnu dot org @ 2009-12-19 19:42 ` rguenth at gcc dot gnu dot org 0 siblings, 0 replies; 3+ messages in thread From: rguenth at gcc dot gnu dot org @ 2009-12-19 19:42 UTC (permalink / raw) To: gcc-bugs ------- Comment #1 from rguenth at gcc dot gnu dot org 2009-12-19 19:42 ------- I'll take care of this during 4.6 development. -- rguenth at gcc dot gnu dot org changed: What |Removed |Added ---------------------------------------------------------------------------- AssignedTo|unassigned at gcc dot gnu |rguenth at gcc dot gnu dot |dot org |org Status|UNCONFIRMED |ASSIGNED Ever Confirmed|0 |1 Last reconfirmed|0000-00-00 00:00:00 |2009-12-19 19:42:12 date| | http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42436 ^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2022-01-13 7:13 UTC | newest] Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- [not found] <bug-42436-4@http.gcc.gnu.org/bugzilla/> 2022-01-12 16:14 ` [Bug tree-optimization/42436] VRP should mark non-trapping integer divisions amacleod at redhat dot com 2022-01-13 7:13 ` rguenth at gcc dot gnu.org 2009-12-19 19:41 [Bug tree-optimization/42436] New: " rguenth at gcc dot gnu dot org 2009-12-19 19:42 ` [Bug tree-optimization/42436] " rguenth at gcc dot gnu dot org
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