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| author | Sanjay Patel <spatel@rotateright.com> | 2019-05-21 18:53:53 +0000 |
|---|---|---|
| committer | Sanjay Patel <spatel@rotateright.com> | 2019-05-21 18:53:53 +0000 |
| commit | 10f6b3989959978e41c2092251a4359fef30d99f (patch) | |
| tree | 429046d5f78c1c9193c67818713bf9f8afcfd551 /llvm | |
| parent | 76e5a1d3c3b107646d88cf91059972c2a2a5f163 (diff) | |
| download | bcm5719-llvm-10f6b3989959978e41c2092251a4359fef30d99f.tar.gz bcm5719-llvm-10f6b3989959978e41c2092251a4359fef30d99f.zip | |
[SelectionDAG] fold insert subvector of undef into undef
DAGCombiner simplifies this more liberally as:
// If inserting an UNDEF, just return the original vector.
if (N1.isUndef())
return N0;
So there's no way to make this visible in output AFAIK, but
doing this at node creation time should be slightly more efficient.
llvm-svn: 361287
Diffstat (limited to 'llvm')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp index 0758a31ec99..366b404b304 100644 --- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp @@ -5367,6 +5367,9 @@ SDValue SelectionDAG::getNode(unsigned Opcode, const SDLoc &DL, EVT VT, break; } case ISD::INSERT_SUBVECTOR: { + // Inserting undef into undef is still undef. + if (N1.isUndef() && N2.isUndef()) + return getUNDEF(VT); SDValue Index = N3; if (VT.isSimple() && N1.getValueType().isSimple() && N2.getValueType().isSimple()) { |
