[PATCH] D52548: Stop instcombining introducing undef's in div/rem instructions.

[Sanjay Patel via Phabricator via llvm-commits]

spatel added a reviewer: RKSimon.
spatel added a comment.

> I found a case where instcombine would introduce an undef into the divisor of a div/rem instruction, which would in turn cause that instruction to be simplified away because 'if any vector component is undef, the whole div/rem is undef.'

I haven't stepped through any of the tests, but before we do that we need to correct this statement. The description only applies to integer ops, not FP. So we need to remove FP div/rem from this patch and/or show how those ops are causing different problems (and that would likely be a different patch).

Please minimize the tests that demonstrate the bug (don't need 'spir func' at least), and commit them to trunk with the current (buggy) output using the script at utils/update_test_checks.py to auto-generate the complete CHECK lines.


Repository:
  rL LLVM

https://reviews.llvm.org/D52548