[SelectionDAG] Teach SelectionDAGBuilder's getUniformBase for gather/scatter handling to accept GEPs with more than 2 operands if the middle operands are all 0s
Currently we can only get a uniform base from a simple GEP with 2 operands. This causes us to miss address folding opportunities for simple global array accesses as the test case shows.
This patch adds support for larger GEPs if the other indices are 0 since those don't require any additional computations to be inserted.
We may also want to handle constant splats of zero here, but I'm leaving that for future work when I have a real world example.
Differential Revision: https://reviews.llvm.org/D39911
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@317947 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed