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* [Bug tree-optimization/96457] New: PRE gets confused by punned load handling @ 2020-08-04 11:44 rguenth at gcc dot gnu.org 2020-08-04 11:44 ` [Bug tree-optimization/96457] " rguenth at gcc dot gnu.org ` (3 more replies) 0 siblings, 4 replies; 5+ messages in thread From: rguenth at gcc dot gnu.org @ 2020-08-04 11:44 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96457 Bug ID: 96457 Summary: PRE gets confused by punned load handling Product: gcc Version: 11.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: tree-optimization Assignee: unassigned at gcc dot gnu.org Reporter: rguenth at gcc dot gnu.org Target Milestone: --- int flag; union { double f; unsigned long long i; } u; void foo(); unsigned long long i; unsigned long long test () { double f = 0.; if (flag) { foo (); f = u.f; } else i = u.i; f = u.f + f; return f; } here we fail to PRE the load of u.f because PHI translation to the else path fails since we run into /* If we'd have to convert things we would need to validate if we can insert the translated expression. So fail here for now - we cannot insert an alias with a different type in the VN tables either, as that would assert. */ if (result && !useless_type_conversion_p (ref->type, TREE_TYPE (result))) return NULL; because we found a value for u.f there, that of u.i (because we value-number them the same). If one replaces 'i = u.i;' with 'foo ();' we appropriately insert a load from u.f in the else path and remove the partial redundancy. ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/96457] PRE gets confused by punned load handling 2020-08-04 11:44 [Bug tree-optimization/96457] New: PRE gets confused by punned load handling rguenth at gcc dot gnu.org @ 2020-08-04 11:44 ` rguenth at gcc dot gnu.org 2020-08-04 12:05 ` rguenth at gcc dot gnu.org ` (2 subsequent siblings) 3 siblings, 0 replies; 5+ messages in thread From: rguenth at gcc dot gnu.org @ 2020-08-04 11:44 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96457 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Ever confirmed|0 |1 Keywords| |missed-optimization Assignee|unassigned at gcc dot gnu.org |rguenth at gcc dot gnu.org Status|UNCONFIRMED |ASSIGNED Last reconfirmed| |2020-08-04 ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/96457] PRE gets confused by punned load handling 2020-08-04 11:44 [Bug tree-optimization/96457] New: PRE gets confused by punned load handling rguenth at gcc dot gnu.org 2020-08-04 11:44 ` [Bug tree-optimization/96457] " rguenth at gcc dot gnu.org @ 2020-08-04 12:05 ` rguenth at gcc dot gnu.org 2021-05-18 7:06 ` rguenth at gcc dot gnu.org 2021-07-28 20:28 ` pinskia at gcc dot gnu.org 3 siblings, 0 replies; 5+ messages in thread From: rguenth at gcc dot gnu.org @ 2020-08-04 12:05 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96457 Richard Biener <rguenth at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Depends on| |88240 --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> --- This also depends on a proper fix for PR88240. Referenced Bugs: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88240 [Bug 88240] [8/9/10/11 Regression] Potential optimization bug: invalid pre-load of floating-point value could cause SIGFPE-underflow if value is integer ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/96457] PRE gets confused by punned load handling 2020-08-04 11:44 [Bug tree-optimization/96457] New: PRE gets confused by punned load handling rguenth at gcc dot gnu.org 2020-08-04 11:44 ` [Bug tree-optimization/96457] " rguenth at gcc dot gnu.org 2020-08-04 12:05 ` rguenth at gcc dot gnu.org @ 2021-05-18 7:06 ` rguenth at gcc dot gnu.org 2021-07-28 20:28 ` pinskia at gcc dot gnu.org 3 siblings, 0 replies; 5+ messages in thread From: rguenth at gcc dot gnu.org @ 2021-05-18 7:06 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96457 Bug 96457 depends on bug 88240, which changed state. Bug 88240 Summary: [9 Regression] Potential optimization bug: invalid pre-load of floating-point value could cause SIGFPE-underflow if value is integer https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88240 What |Removed |Added ---------------------------------------------------------------------------- Status|ASSIGNED |RESOLVED Resolution|--- |FIXED ^ permalink raw reply [flat|nested] 5+ messages in thread
* [Bug tree-optimization/96457] PRE gets confused by punned load handling 2020-08-04 11:44 [Bug tree-optimization/96457] New: PRE gets confused by punned load handling rguenth at gcc dot gnu.org ` (2 preceding siblings ...) 2021-05-18 7:06 ` rguenth at gcc dot gnu.org @ 2021-07-28 20:28 ` pinskia at gcc dot gnu.org 3 siblings, 0 replies; 5+ messages in thread From: pinskia at gcc dot gnu.org @ 2021-07-28 20:28 UTC (permalink / raw) To: gcc-bugs https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96457 Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Severity|normal |enhancement Last reconfirmed|2020-08-04 00:00:00 |2021-7-28 ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2021-07-28 20:28 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-08-04 11:44 [Bug tree-optimization/96457] New: PRE gets confused by punned load handling rguenth at gcc dot gnu.org 2020-08-04 11:44 ` [Bug tree-optimization/96457] " rguenth at gcc dot gnu.org 2020-08-04 12:05 ` rguenth at gcc dot gnu.org 2021-05-18 7:06 ` rguenth at gcc dot gnu.org 2021-07-28 20:28 ` pinskia at gcc dot gnu.org
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