Inverse of ValueMap from virtual register to IR value.
Declared in <llvm/CodeGen/FunctionLoweringInfo.h>
DenseMap<Register, Value const*> VirtReg2Value;VirtReg2Value map is needed by the Divergence Analysis driven instruction selection. It is reverted ValueMap. It is computed in lazy style - on demand. It is used to get the Value corresponding to the live in virtual register and is called from the TargetLowerinInfo::isSDNodeSourceOfDivergence.