[llvm-dev] SCEV on vector element

[Darshan Bhat via llvm-dev]

Is it possible to get a meaningful SCEV expression on a vector element ?

I am having a vector and I am extracting an element using "extractelement" instruction like below :

 %2 = extractelement <5 x i32> %vecins32, i32 0

The extracted value will be a scalar. This value is being set in each iteration of a loop. I want to see how this value is getting incremented.

Is it possible to run Scalar Evolution analysis on this and get a meaningful SCEV expression ?

[Philip Reames via llvm-dev]

SCEV currently does not model vector expressions. 

We could in theory extend SCEV to vector types, and I've given that a tiny bit of thought.  At the moment, I'm not convinced that such an extension is worthwhile.  Even if worthwhile, it's a very substantial piece of work.

Philip

_______________________________________________
LLVM Developers mailing list
llvm...@lists.llvm.org
https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev