[PATCH] D13851: [X86][XOP] Add support for lowering vector rotations

Elena Demikhovsky via llvm-commits llvm-commits at lists.llvm.org
Wed Oct 21 00:36:49 PDT 2015


delena added a comment.

In http://reviews.llvm.org/D13851#271535, @RKSimon wrote:

> Updated with 256-bit tests. I've removed ROTR lowering from XOP for now - we don't have any combines that just create ROTR (all attempt to lower with either ROTL/ROTR depending on what is legal/custom), so we can avoid the extra cost of the subtract and always use ROTL on XOP.


The rotation immediate can be negative. It will mean rotation right. I assume that the combiner catches this scenario and generates ROTL with negative value. Could you, please, add a test for this?


Repository:
  rL LLVM

http://reviews.llvm.org/D13851





More information about the llvm-commits mailing list