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* [Bug tree-optimization/95729] New: Failure to optimize away certain returns when the condition to reach them is a calculation that already results in that value @ 2020-06-17 20:17 gabravier at gmail dot com 2020-06-17 22:14 ` [Bug tree-optimization/95729] " pinskia at gcc dot gnu.org ` (3 more replies) 0 siblings, 4 replies; 5+ messages in thread From: gabravier at gmail dot com @ 2020-06-17 20:17 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95729 Bug ID: 95729 Summary: Failure to optimize away certain returns when the condition to reach them is a calculation that already results in that value Product: gcc Version: 11.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: gabravier at gmail dot com Target Milestone: --- int f(int a, int b) { if (a != b) return a - b; else return 0; } This can be optimized to `return a - b;`. This optimization is done by LLVM, but not by GCC. ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/95729] Failure to optimize away certain returns when the condition to reach them is a calculation that already results in that value 2020-06-17 20:17 [Bug tree-optimization/95729] New: Failure to optimize away certain returns when the condition to reach them is a calculation that already results in that value gabravier at gmail dot com @ 2020-06-17 22:14 ` pinskia at gcc dot gnu.org 2020-06-18 8:39 ` rguenth at gcc dot gnu.org ` (2 subsequent siblings) 3 siblings, 0 replies; 5+ messages in thread From: pinskia at gcc dot gnu.org @ 2020-06-17 22:14 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95729 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Severity|normal |enhancement ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/95729] Failure to optimize away certain returns when the condition to reach them is a calculation that already results in that value 2020-06-17 20:17 [Bug tree-optimization/95729] New: Failure to optimize away certain returns when the condition to reach them is a calculation that already results in that value gabravier at gmail dot com 2020-06-17 22:14 ` [Bug tree-optimization/95729] " pinskia at gcc dot gnu.org @ 2020-06-18 8:39 ` rguenth at gcc dot gnu.org 2021-11-17 9:41 ` pinskia at gcc dot gnu.org 2023-05-06 23:12 ` pinskia at gcc dot gnu.org 3 siblings, 0 replies; 5+ messages in thread From: rguenth at gcc dot gnu.org @ 2020-06-18 8:39 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95729 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |NEW Last reconfirmed| |2020-06-18 Ever confirmed|0 |1 --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- Confirmed. Sth for phiopt and/or a cond_expr match.pd pattern (which phiopt could exercise btw). a != b ? a - b : 0 -> a - b ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/95729] Failure to optimize away certain returns when the condition to reach them is a calculation that already results in that value 2020-06-17 20:17 [Bug tree-optimization/95729] New: Failure to optimize away certain returns when the condition to reach them is a calculation that already results in that value gabravier at gmail dot com 2020-06-17 22:14 ` [Bug tree-optimization/95729] " pinskia at gcc dot gnu.org 2020-06-18 8:39 ` rguenth at gcc dot gnu.org @ 2021-11-17 9:41 ` pinskia at gcc dot gnu.org 2023-05-06 23:12 ` pinskia at gcc dot gnu.org 3 siblings, 0 replies; 5+ messages in thread From: pinskia at gcc dot gnu.org @ 2021-11-17 9:41 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95729 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Assignee|unassigned at gcc dot gnu.org |pinskia at gcc dot gnu.org Status|NEW |ASSIGNED --- Comment #2 from Andrew Pinski <pinskia at gcc dot gnu.org> --- ;; a != b ? a - b : 0 Something like: (simplify (cond (ne:c @0 @1) (minus@2 @0 @1) zero_p) (if (!HONOR_NANS (type) && !HONOR_SIGNED_ZEROS (type)) @2) (simplify (cond (eq:c @0 @1) zero_p (minus@2 @0 @1)) (if (!HONOR_NANS (type) && !HONOR_SIGNED_ZEROS (type)) @2) Note I noticed LLVM 13 no longer does this optimization (I wonder if they have a testsuite). ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/95729] Failure to optimize away certain returns when the condition to reach them is a calculation that already results in that value 2020-06-17 20:17 [Bug tree-optimization/95729] New: Failure to optimize away certain returns when the condition to reach them is a calculation that already results in that value gabravier at gmail dot com ` (2 preceding siblings ...) 2021-11-17 9:41 ` pinskia at gcc dot gnu.org @ 2023-05-06 23:12 ` pinskia at gcc dot gnu.org 3 siblings, 0 replies; 5+ messages in thread From: pinskia at gcc dot gnu.org @ 2023-05-06 23:12 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95729 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|ASSIGNED |RESOLVED Resolution|--- |DUPLICATE --- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> --- basically an exact dup of bug 19832. *** This bug has been marked as a duplicate of bug 19832 *** ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2023-05-06 23:12 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-06-17 20:17 [Bug tree-optimization/95729] New: Failure to optimize away certain returns when the condition to reach them is a calculation that already results in that value gabravier at gmail dot com 2020-06-17 22:14 ` [Bug tree-optimization/95729] " pinskia at gcc dot gnu.org 2020-06-18 8:39 ` rguenth at gcc dot gnu.org 2021-11-17 9:41 ` pinskia at gcc dot gnu.org 2023-05-06 23:12 ` pinskia at gcc dot gnu.org
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