[PATCH] D26726: [SimplifyCFG] Fix for non-determinism in codegen

[Mandeep Singh Grang via Phabricator via llvm-commits]

mgrang added a comment.

@arsenm @davide Yes, it's difficult to make a test case for this. I uncovered this issue by turning ON reverse iteration of SmallPtrSet and finding that the following unit test failed:

test/Transforms/SimplifyCFG/bug-25299.ll

It failed because it expects:
continue:                                         ; preds = %entry, %continue

But due to reverse iteration we get:
continue:                                         ; preds = %continue, %entry

So, isn't the failing of this test case in itself sufficient to demonstrate the validity/correctness of this patch?

As far as the compile time is concerned, let me try building some tests and measure the effect on compile time.


Repository:
  rL LLVM

https://reviews.llvm.org/D26726