Give up on register class recalculation when the register is used with subreg operands. We don't currently have a hook to provide "the largest super class of A where all registers' getSubReg(subidx) is valid and in B".
Give up on register class recalculation when the register is used with subreg
operands. We don't currently have a hook to provide "the largest super class of
A where all registers' getSubReg(subidx) is valid and in B".

git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@110730 91177308-0d34-0410-b5e6-96231b3b80d8

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