[MachineVerifier] Include offending register in allocatable live-in error msg.
[MachineVerifier] Include offending register in allocatable live-in error msg.

This patch adds a convenience report() method for physical registers and
uses it to print the offending register with the 'MBB has allocatable
live-in' error.

Reviewers: MatzeB, rtereshin, dsanders

Reviewed By: dsanders

Differential Revision: https://reviews.llvm.org/D55946


git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@350630 91177308-0d34-0410-b5e6-96231b3b80d8

apple/swift-llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm