diff options
| author | Chris Lattner <sabre@nondot.org> | 2010-01-02 00:00:03 +0000 |
|---|---|---|
| committer | Chris Lattner <sabre@nondot.org> | 2010-01-02 00:00:03 +0000 |
| commit | 1eea3b0adab77358000e56cbf0804290a0c96375 (patch) | |
| tree | 2851a96e3d6e78c92d9b68095e35f0b864031e8b /llvm/lib/CodeGen/SelectionDAG | |
| parent | 6eef072eb67cf17952e39dcb0814cf2d29978f4b (diff) | |
| download | bcm5719-llvm-1eea3b0adab77358000e56cbf0804290a0c96375.tar.gz bcm5719-llvm-1eea3b0adab77358000e56cbf0804290a0c96375.zip | |
Teach codegen to handle:
(X != null) | (Y != null) --> (X|Y) != 0
(X == null) & (Y == null) --> (X|Y) == 0
so that instcombine can stop doing this for pointers. This is part of PR3351,
which is a case where instcombine doing this for pointers (inserting ptrtoint)
is pessimizing code.
llvm-svn: 92406
Diffstat (limited to 'llvm/lib/CodeGen/SelectionDAG')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp index 74d624f3647..40eb9eeb82a 100644 --- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp @@ -1195,6 +1195,18 @@ SelectionDAGBuilder::ShouldEmitAsBranches(const std::vector<CaseBlock> &Cases){ return false; } + // Handle: (X != null) | (Y != null) --> (X|Y) != 0 + // Handle: (X == null) & (Y == null) --> (X|Y) == 0 + if (Cases[0].CmpRHS == Cases[1].CmpRHS && + Cases[0].CC == Cases[1].CC && + isa<Constant>(Cases[0].CmpRHS) && + cast<Constant>(Cases[0].CmpRHS)->isNullValue()) { + if (Cases[0].CC == ISD::SETEQ && Cases[0].TrueBB == Cases[1].ThisBB) + return false; + if (Cases[0].CC == ISD::SETNE && Cases[0].FalseBB == Cases[1].ThisBB) + return false; + } + return true; } |
