diff options
Diffstat (limited to 'llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp')
| -rw-r--r-- | llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp index 0f351975b9d..a8a76311225 100644 --- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -3775,20 +3775,25 @@ SDValue DAGCombiner::visitOR(SDNode *N) { int M0 = SV0->getMaskElt(i); int M1 = SV1->getMaskElt(i); - // Both shuffle indexes are undef. Propagate Undef. - if (M0 < 0 && M1 < 0) { + // Determine if either index is pointing to a zero vector. + bool M0Zero = M0 < 0 || (ZeroN00 == (M0 < NumElts)); + bool M1Zero = M1 < 0 || (ZeroN10 == (M1 < NumElts)); + + // If one element is zero and the otherside is undef, keep undef. + // This also handles the case that both are undef. + if ((M0Zero && M1 < 0) || (M1Zero && M0 < 0)) { Mask[i] = -1; continue; } - // Determine if either index is pointing to a zero vector. - bool M0Zero = M0 >= 0 && (ZeroN00 == (M0 < NumElts)); - bool M1Zero = M1 >= 0 && (ZeroN10 == (M1 < NumElts)); + // Make sure only one of the elements is zero. if (M0Zero == M1Zero) { CanFold = false; break; } + assert((M0 >= 0 || M1 >= 0) && "Undef index!"); + // We have a zero and non-zero element. If the non-zero came from // SV0 make the index a LHS index. If it came from SV1, make it // a RHS index. We need to mod by NumElts because we don't care |
