LLVM Bugzilla is read-only and represents the historical archive of all LLVM issues filled before November 26, 2021. Use github to submit LLVM bugs

Bug 32407 - Merge r298687 into the 4.0 branch : NewGVN: Fix PR32403 - Handling of undef in phis was not quite correct
Summary: Merge r298687 into the 4.0 branch : NewGVN: Fix PR32403 - Handling of undef i...
Status: RESOLVED WONTFIX
Alias: None
Product: new-bugs
Classification: Unclassified
Component: new bugs (show other bugs)
Version: 4.0
Hardware: All All
: P enhancement
Assignee: Tom Stellard
URL: https://reviews.llvm.org/rL298687
Keywords:
Depends on:
Blocks: release-4.0.1
  Show dependency tree
 
Reported: 2017-03-24 07:58 PDT by Tom Stellard
Modified: 2017-05-19 11:53 PDT (History)
3 users (show)

See Also:
Fixed By Commit(s):

Attachments
Add an attachment (proposed patch, testcase, etc.)

Note You need to log in before you can comment on or make changes to this bug.
Description Tom Stellard 2017-03-24 07:58:31 PDT 
Is this patch OK to merge to the 4.0 branch?
Comment 1 Davide Italiano 2017-03-24 14:18:28 PDT 
I think so.
Comment 2 Daniel Berlin 2017-03-24 15:34:58 PDT 
Yes.
Comment 3 Daniel Berlin 2017-03-24 15:36:32 PDT 
Note that this revision is the strictly smallest fix.
I refactored it into a faster test that usually does not require checking all members of the congruence class.

But i don't expect this to occur commonly enough to ever matter performance wise.
Comment 4 Tom Stellard 2017-04-04 08:56:03 PDT 
This commit depends on r297424, which we can't merge because it breaks the ABI.
Comment 5 Daniel Berlin 2017-04-04 10:09:55 PDT 
Two options:
1.It's possible to rework the code to not depend on that if you like.
It should just be de-constifying some tings
2. You can avoid breaking the ABI by just adding back the old versions of the count and lookup functions, no?
Comment 6 Tom Stellard 2017-05-19 08:16:37 PDT 
Is anyone interested in fixing up this patch to merge?
Comment 7 Daniel Berlin 2017-05-19 08:19:28 PDT 
There's more you'd have to merge as i'm about to fix pr32838, a related issue.

Unless someone has a strong urge to have it in 4.0, ...
Comment 8 Davide Italiano 2017-05-19 11:53:29 PDT 
Thanks for pinging and reminding me of this one, Tom!
I'm making a call here and resolving it as WONTFIX.
Backporting just this very issue isn't really helping as in the meanwhile we fixed a bunch of miscompiles/crashes/etc..

Backporting all of them seems unrealistic in the 4.0.1 timeframe.