[polly] r272001 - [FIX] Model the rounding behaviour of SRem correctly

[Tobias Grosser via llvm-commits]

On 06/07/2016 02:00 PM, Johannes Doerfert via llvm-commits wrote:
> Author: jdoerfert
> Date: Tue Jun  7 07:00:37 2016
> New Revision: 272001
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=272001&view=rev
> Log:
> [FIX] Model the rounding behaviour of SRem correctly

It seems the only functional change is the use of isl_pw_aff_tdiv_r
instead of isl_pw_aff_mod_val, right?

It would be helpful to point this out in the commit message and explain
_why_ the original behavior was wrong and how the new behavior is more
correct.

I assume mod_val has different rounding behavior than tdiv_r, right?
Pointing out what the semantics of LLVM-IR and the operations in
question are would allow people to easily follow your reasoning without
the need to lookup the precise semantics in the source code.

Best,
Tobias