Conversation
vtjnash
commented
Sep 28, 2021
Comment on lines
-8219
to
-8220
| const char *const argv_avoidsfb[] = {"", "-x86-disable-avoid-SFB"}; // llvm bug 41629, see https://gist.github.com/vtjnash/192cab72a6cfc00256ff118238163b55 | ||
| cl::ParseCommandLineOptions(sizeof(argv_avoidsfb)/sizeof(argv_avoidsfb[0]), argv_avoidsfb, "disable-avoidsfb\n"); |
Member
Author
There was a problem hiding this comment.
https://bugs.llvm.org/show_bug.cgi?id=41629 fixed by
$ git show 8172ed91f8ff753fb
commit 8172ed91f8ff753fb3042f39b0d43aed89fdd3e6
Author: Craig Topper <craig.topper@intel.com>
Date: Wed Jun 24 00:10:36 2020 -0700
[X86] Speculatively fix to X86AvoidStoreForwardingBlocks not deference a machine mem operand if there isn't one present.
Eric Christopher informed me that FastISel memcpy handling creates
load/store instructions without mem operands. We should fix that,
but I doubt that's the only case of missed mem operands so seems
better to be defensive here.
I don't have a test case yet, but I'll try to add one if i get a
test from Eric.
Comment on lines
-8215
to
-8216
| const char *const argv_copyprop[] = {"", "-disable-copyprop"}; // llvm bug 21743 | ||
| cl::ParseCommandLineOptions(sizeof(argv_copyprop)/sizeof(argv_copyprop[0]), argv_copyprop, "disable-copyprop\n"); |
Member
Author
There was a problem hiding this comment.
https://bugs.llvm.org/show_bug.cgi?id=21743 fixed by
commit 796d906e06f8f5a3c8d4f5f0faa5c47697153490
Author: Quentin Colombet <qcolombet@apple.com>
Date: Thu Apr 23 21:17:39 2015 +0000
[MachineCopyPropagation] Handle undef flags conservatively so that we do not
remove copies that are useful after breaking some hardware dependencies.
In other words, handle this kind of situations conservatively by assuming reg2
is redefined by the undef flag.
reg1 = copy reg2
= inst reg2<undef>
reg2 = copy reg1
Copy propagation used to remove the last copy.
This is incorrect because the undef flag on reg2 in inst, allows next
passes to put whatever trashed value in reg2 that may help.
In practice we end up with this code:
reg1 = copy reg2
reg2 = 0
= inst reg2<undef>
reg2 = copy reg1
This fixes PR21743.
llvm-svn: 235647
JeffBezanson
approved these changes
Sep 28, 2021
vchuravy
reviewed
Sep 28, 2021
vchuravy
approved these changes
Sep 28, 2021
LilithHafner
pushed a commit
to LilithHafner/julia
that referenced
this pull request
Feb 22, 2022
LilithHafner
pushed a commit
to LilithHafner/julia
that referenced
this pull request
Mar 8, 2022
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
4 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
These just don't need to be so verbose and hard-coded.