PR target/38900
	* config/i386/i386.h (CONDITIONAL_REGISTER_USAGE): Move to i386.c.
	(enum reg_class): Add CLOBBERED_REGS.
	(REG_CLASS_NAMES, REG_CLASS_CONTENTS): Likewise.
	* config/i386/i386.c (ix86_conditional_register_usage): Moved
	from CONDITIONAL_REGISTER_USAGE; build CLOBBERED_REGS for 64-bit.
	(ix86_function_ok_for_sibcall): Tidy.  Disallow MS->SYSV sibcalls.
	(ix86_expand_call): Use sibcall_insn_operand when needed.  Don't
	force 64-bit sibcalls into R11.
	* config/i386/constraints.md (U): New constraint.
	* config/i386/i386.md (sibcall_1, sibcall_value_1): Use it.
	(sibcall_1_rex64, sibcall_value_1_rex64): Likewise.
	(sibcall_1_rex64_v, sibcall_value_1_rex64_v): Remove.

From-SVN: r149373