DAGCombiner: Extend reduceBuildVecToTrunc to handle non-zero offset
Summary:
Adding support for combining power2-strided build_vector's where the
first build_vectori's operand is extracted from a non-zero index.
Example:
v4i32 build_vector((extract_elt V, 1),
(extract_elt V, 3),
(extract_elt V, 5),
(extract_elt V, 7))
-->
v4i32 truncate (bitcast (shuffle<1,u,3,u,5,u,7,u> V, u) to v4i64)
Reviewers: delena, RKSimon, guyblank
Reviewed By: RKSimon
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D35700
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@309108 91177308-0d34-0410-b5e6-96231b3b80d8
7 files changed