[flang-commits] [clang] [flang] [flang] add -floop-interchange and enable it with opt levels (PR #140182)

[Sebastian Pop via flang-commits]

sebpop wrote:

> Generally assume best intentions.

I agree, and I will keep this in mind.

> These issues aren't caught by assertions and can silently lead to incorrect transformations.

For GCC, I adapted the Omega test (from Bill Pugh) to produce the same representation as the classic dependence tests.  And we got more confidence that the dependence analysis implementation was correct. I removed the extra checks https://github.com/gcc-mirror/gcc/commit/49b8fe6c1a585edfeb5dd0f292e05a167f475f68 10 years down the road.

Maybe we could do the same to build trust in the results provided by LLVM's DA.
We could adapt Polly to print distance and direction vectors and then diff DA against Polly.

https://github.com/llvm/llvm-project/pull/140182