llvm.org GIT mirror llvm / 2886506
Add a comment to describe why vector shuffles are legalized to custom DAG nodes. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@78884 91177308-0d34-0410-b5e6-96231b3b80d8 Bob Wilson 10 years ago
1 changed file(s) with 4 addition(s) and 0 deletion(s). Raw diff Collapse all Expand all
24382438 DebugLoc dl = Op.getDebugLoc();
24392439 EVT VT = Op.getValueType();
24402440
2441 // Convert shuffles that are directly supported on NEON to target-specific
2442 // DAG nodes, instead of keeping them as shuffles and matching them again
2443 // during code selection. This is more efficient and avoids the possibility
2444 // of inconsistencies between legalization and selection.
24412445 if (SVN->isSplat() && SVN->getSplatIndex() == 0)
24422446 return DAG.getNode(ARMISD::VSPLAT0, dl, VT, SVN->getOperand(0));
24432447 if (isVREVMask(SVN, 64))