diff options
Diffstat (limited to 'llvm/lib/CodeGen')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 34 |
1 files changed, 24 insertions, 10 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index e8cbd8af7a8..603ccb090ed 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -10838,16 +10838,30 @@ SDValue DAGCombiner::visitVECTOR_SHUFFLE(SDNode *N) { // It may still be beneficial to combine the two shuffles if the // resulting shuffle is legal. - if (TLI.isTypeLegal(VT) && TLI.isShuffleMaskLegal(Mask, VT)) { - if (!CommuteOperands) - // shuffle(shuffle(x, undef, M1), undef, M2) -> shuffle(x, undef, M3). - // shuffle(shuffle(x, y, M1), undef, M2) -> shuffle(x, undef, M3) - return DAG.getVectorShuffle(VT, SDLoc(N), N0->getOperand(0), N1, - &Mask[0]); - - // shuffle(shuffle(x, y, M1), undef, M2) -> shuffle(undef, y, M3) - return DAG.getVectorShuffle(VT, SDLoc(N), N1, N0->getOperand(1), - &Mask[0]); + if (TLI.isTypeLegal(VT)) { + if (!CommuteOperands) { + if (TLI.isShuffleMaskLegal(Mask, VT)) + // shuffle(shuffle(x, undef, M1), undef, M2) -> shuffle(x, undef, M3). + // shuffle(shuffle(x, y, M1), undef, M2) -> shuffle(x, undef, M3) + return DAG.getVectorShuffle(VT, SDLoc(N), N0->getOperand(0), N1, + &Mask[0]); + } else { + // Compute the commuted shuffle mask. + for (unsigned i = 0; i != NumElts; ++i) { + int idx = Mask[i]; + if (idx < 0) + continue; + else if (idx < (int)NumElts) + Mask[i] = idx + NumElts; + else + Mask[i] = idx - NumElts; + } + + if (TLI.isShuffleMaskLegal(Mask, VT)) + // shuffle(shuffle(x, y, M1), undef, M2) -> shuffle(y, undef, M3) + return DAG.getVectorShuffle(VT, SDLoc(N), N0->getOperand(1), N1, + &Mask[0]); + } } } |
