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| author | Nirav Dave <niravd@google.com> | 2017-07-20 13:48:17 +0000 |
|---|---|---|
| committer | Nirav Dave <niravd@google.com> | 2017-07-20 13:48:17 +0000 |
| commit | 77cc6f23b99f7693f1552470ecc0081a712c7987 (patch) | |
| tree | 345660e6542a34247110d15eb6b2fdbefe4fb09a /llvm/lib | |
| parent | d9e9e44baa859d2335ca180cb879f86c2ea886d6 (diff) | |
| download | bcm5719-llvm-77cc6f23b99f7693f1552470ecc0081a712c7987.tar.gz bcm5719-llvm-77cc6f23b99f7693f1552470ecc0081a712c7987.zip | |
[DAG] Optimize away degenerate INSERT_VECTOR_ELT nodes.
Summary:
Add missing vector write of vector read reduction, i.e.:
(insert_vector_elt x (extract_vector_elt x idx) idx) to x
Reviewers: spatel, RKSimon, efriedma
Reviewed By: RKSimon
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D35563
llvm-svn: 308617
Diffstat (limited to 'llvm/lib')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 535b272f793..50cad23a00a 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -13572,6 +13572,12 @@ SDValue DAGCombiner::visitINSERT_VECTOR_ELT(SDNode *N) { EVT VT = InVec.getValueType(); + // Remove redundant insertions: + // (insert_vector_elt x (extract_vector_elt x idx) idx) -> x + if (InVal.getOpcode() == ISD::EXTRACT_VECTOR_ELT && + InVec == InVal->getOperand(0) && EltNo == InVal->getOperand(1)) + return InVec; + // Check that we know which element is being inserted if (!isa<ConstantSDNode>(EltNo)) return SDValue(); |
