[TargetLowering][DAGCombine][MSP430] Shift Amount Threshold in DAGCombine (4)
unsigned getShiftAmountThreshold(EVT VT)
bool shouldAvoidTransformToShift(EVT VT, unsigned amount)
thus giving more flexibility for targets to decide whether particular shift amounts must be considered expensive or not.
Updates the MSP430 target with a custom implementation.
Existing tests apply, a few more have been added.
Reviewers: asl, spatel
Reviewed By: spatel
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D70042