[polly] r271878 - Use minimal types for generated expressions

[Tobias Grosser via llvm-commits]

On 06/06/2016 11:57 AM, Johannes Doerfert via llvm-commits wrote:
> Author: jdoerfert
> Date: Mon Jun  6 04:57:41 2016
> New Revision: 271878
> 
> URL: http://llvm.org/viewvc/llvm-project?rev=271878&view=rev
> Log:
> Use minimal types for generated expressions
> 
>   We now use the minimal necessary bit width for the generated code. If
>   operations might overflow (add/sub/mul) we will try to adjust the types in
>   order to ensure a non-wrapping computation. If the type adjustment is not
>   possible, thus the necessary type is bigger than the type value of
>   --polly-max-expr-bit-width, we will use assumptions to verify the computation
>   will not wrap. However, for run-time checks we cannot build assumptions but
>   instead utilize overflow tracking intrinsics.

Hi Johannes,

this patch is rather intrusive and also warrants a design discussion. I
would like to do a pre-commit review here. Could we possibly revert this
patch to ensure that no further history builds up on this patch?

Best,
Tobias