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| author | Evan Cheng <evan.cheng@apple.com> | 2006-01-06 01:06:31 +0000 |
|---|---|---|
| committer | Evan Cheng <evan.cheng@apple.com> | 2006-01-06 01:06:31 +0000 |
| commit | da95a84a11e684072ea25fbb9830e769039fd985 (patch) | |
| tree | 023a6eed0ee8c3e06bc2eaff95441d072fe9d837 /lib/CodeGen/SelectionDAG/DAGCombiner.cpp | |
| parent | a35ef6350defdc09eb912c52603cffa6afbd78e2 (diff) | |
fold (shl x, 1) -> (add x, x)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@25120 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/SelectionDAG/DAGCombiner.cpp')
| -rw-r--r-- | lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 30a4c9f637..9770ae232b 100644 --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -1282,6 +1282,9 @@ SDOperand DAGCombiner::visitSHL(SDNode *N) { // fold (shl x, 0) -> x if (N1C && N1C->isNullValue()) return N0; + // fold (shl x, 1) -> (add x, x) + if (N1C && N1C->getValue() == 1) + return DAG.getNode(ISD::ADD, VT, N0, N0); // if (shl x, c) is known to be zero, return 0 if (N1C && MaskedValueIsZero(SDOperand(N, 0), ~0ULL >> (64-OpSizeInBits),TLI)) return DAG.getConstant(0, VT); |