[PATCH] D20775: [CFLAA] Remove redundant aliasing relation between GEP indices and GEP result

[Jia Chen via llvm-commits]

grievejia added a comment.

In http://reviews.llvm.org/D20775#443337, @dberlin wrote:

> Hey Jia,
>  You need to add testcases for this :)


I tried and found it pretty hard to come up with a test case that can target this particular patch specifically.

The issue here is that the gep indices must be integers. To test for aliasing relation between a gep result and another pointer that acts like a gep index, there must be a ptr-to-int cast or an int-to-ptr cast. Cfl-aa is currently very conservative about both inttoptr and ptrtoint. Therefore as long as the inttoptr/ptrtoint handling stays the same, it's not possible for this patch to alter the behavior of cfl-aa in any observable way!

I'll try to upload another patch later that fix this issue by making cfl-aa treats ptrtoint as a no-op. Is it ok if I attach the test cases to that patch instead?


http://reviews.llvm.org/D20775