i386: Update -mfunction-return= for return with pop

i386: Update -mfunction-return= for return with pop

When -mfunction-return= is used, simple_return_pop_internal should pop
return address into ECX register, adjust stack by bytes to pop from stack
and jump to the return thunk via ECX register.

Tested on i686 and x86-64.

	PR target/84530
	* config/i386/i386-protos.h (ix86_output_indirect_jmp): Remove
	the bool argument.
	(ix86_output_indirect_function_return): New prototype.
	(ix86_split_simple_return_pop_internal): Likewise.
	* config/i386/i386.c (indirect_return_via_cx): New.
	(indirect_return_via_cx_bnd): Likewise.
	(indirect_thunk_name): Handle return va CX_REG.
	(output_indirect_thunk_function): Create alias for
	__x86_return_thunk_[re]cx and __x86_return_thunk_[re]cx_bnd.
	(ix86_output_indirect_jmp): Remove the bool argument.
	(ix86_output_indirect_function_return): New function.
	(ix86_split_simple_return_pop_internal): Likewise.
	* config/i386/i386.md (*indirect_jump): Don't pass false
	to ix86_output_indirect_jmp.
	(*tablejump_1): Likewise.
	(simple_return_pop_internal): Change it to define_insn_and_split.
	Call ix86_split_simple_return_pop_internal to split it for
	-mfunction-return=.
	(simple_return_indirect_internal): Call
	ix86_output_indirect_function_return instead of
	ix86_output_indirect_jmp.

gcc/testsuite/

	PR target/84530
	* gcc.target/i386/ret-thunk-22.c: New test.
	* gcc.target/i386/ret-thunk-23.c: Likewise.
	* gcc.target/i386/ret-thunk-24.c: Likewise.
	* gcc.target/i386/ret-thunk-25.c: Likewise.
	* gcc.target/i386/ret-thunk-26.c: Likewise.

From-SVN: r257992