Added checking code whehter target supports specific dag combining about rotate
or not. The corresponding dag patterns are as following:
"DAGCombier::MatchRotate" function in DAGCombiner.cpp
Pattern1
// fold (or (shl (*ext x), (*ext y)),
// (srl (*ext x), (*ext (sub 32, y)))) ->
// (*ext (rotl x, y))
// fold (or (shl (*ext x), (*ext y)),
// (srl (*ext x), (*ext (sub 32, y)))) ->
// (*ext (rotr x, (sub 32, y)))
pattern2
// fold (or (shl (*ext x), (*ext (sub 32, y))),
// (srl (*ext x), (*ext y))) ->
// (*ext (rotl x, y))
// fold (or (shl (*ext x), (*ext (sub 32, y))),
// (srl (*ext x), (*ext y))) ->
// (*ext (rotr x, (sub 32, y)))
llvm-svn: 191905
1 file changed