Fix: prevent copy elimination for statement which does not support constant values #3512
Conversation
This file contains 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
mihaibudiu
approved these changes
Sep 6, 2022
| @@ -355,22 +355,100 @@ CopyPropagationAndElimination::copyPropAndDeadCodeElim( | |||
| } else if (auto jc = stmt->to<IR::DpdkJmpLessStatement>()) { | |||
| instr.push_back(new IR::DpdkJmpLessStatement(jc->label, | |||
| replaceIfCopy(jc->src1, false), replaceIfCopy(jc->src2))); | |||
| } else if (auto jc = stmt->to<IR::DpdkJmpLessOrEqualStatement>()) { | |||
There was a problem hiding this comment.
this implementation now has a lot of redundancy, I suspect you could do much better by using a visitor with a preorder rmethod on the base classes. But this will work.
There was a problem hiding this comment.
I would like to create a new PR for refactoring.
| return false; | ||
| } | ||
|
|
||
| bool preorder(const IR::DpdkBinaryStatement *b) override { | ||
| usesInfo[b->src1->toString()]++; | ||
| usesInfo[b->src2->toString()]++; | ||
| defInfo[b->dst->toString()]++; | ||
| // dst and src1 can not be eliminated, because both are same | ||
| // and dpdk does not allow src1 to be constant | ||
| dontEliminate[b->dst->toString()] = true; |
There was a problem hiding this comment.
it looks to me like this could be a helper function which takes an expression.
that could be useful particularly if later you decide to change the way you represent the "dontEliminate" information.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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Outdated suggestions cannot be applied.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.
dpdk does not expect operands of some of the statements as constant this pr prevent copy prop and elimination for those stmts.