uint64_t &KnownOne,
unsigned Depth = 0) const;
+ /// ComputeNumSignBits - Return the number of times the sign bit of the
+ /// register is replicated into the other bits. We know that at least 1 bit
+ /// is always equal to the sign bit (itself), but other cases can give us
+ /// information. For example, immediately after an "SRA X, 2", we know that
+ /// the top 3 bits are all equal to each other, so we return 3.
+ unsigned ComputeNumSignBits(SDOperand Op, unsigned Depth = 0) const;
+
+ /// ComputeNumSignBitsForTargetNode - This method can be implemented by
+ /// targets that want to expose additional information about sign bits to the
+ /// DAG Combiner.
+ virtual unsigned ComputeNumSignBitsForTargetNode(SDOperand Op,
+ unsigned Depth = 0) const;
+
struct DAGCombinerInfo {
void *DC; // The DAG Combiner object.
bool BeforeLegalize;