llvm::TargetLowering::ComputeNumSignBitsForTargetNode

Synopsis

Declared in <llvm/CodeGen/TargetLowering.h>

virtual
unsigned int
ComputeNumSignBitsForTargetNode(
    SDValue Op,
    APInt const& DemandedElts,
    SelectionDAG const& DAG,
    unsigned int Depth = 0) const;

Description

This method can be implemented by targets that want to expose additional information about sign bits to the DAG Combiner. The DemandedElts argument allows us to only collect the minimum sign bits that are shared by the requested vector elements.

Return Value

The number of known sign bits for a target-specific SelectionDAG node.

Parameters

Name	Description
Op	SDNode or value being queried.
DemandedElts	Mask of vector elements that are demanded.
DAG	SelectionDAG providing context.
Depth	Recursion depth limit for the analysis.