GHC.CmmToAsm.Reg.Regs

A set of registers, with their respective formats, mostly for use in register liveness analysis. See Note [Register formats in liveness analysis] in GHC.CmmToAsm.Reg.Liveness.

Remove 2nd argument registers from the 1st argument, but only if the format in the second argument is at least as large as the format in the first argument.

Remove 2nd argument registers from the 1st argument, regardless of format.

See also minusCoveredRegs, which looks at the formats.

Computes the set of registers in both arguments whose size is smaller in the second argument than in the first.

Map a function that may change the Unique of the register, which entails going via lists.

See Note [UniqSet invariant] in GHC.Types.Unique.Set.