18.9.16 Miscellaneous register hooks

Target Hook: bool TARGET_CALL_FUSAGE_CONTAINS_NON_CALLEE_CLOBBERS

Set to true if each call that binds to a local definition explicitly clobbers or sets all non-fixed registers modified by performing the call. That is, by the call pattern itself, or by code that might be inserted by the linker (e.g. stubs, veneers, branch islands), but not including those modifiable by the callee. The affected registers may be mentioned explicitly in the call pattern, or included as clobbers in CALL_INSN_FUNCTION_USAGE. The default version of this hook is set to false. The purpose of this hook is to enable the fipa-ra optimization.