* reg-stack.c (compare_for_stack_reg): Add bool argument.

	* reg-stack.c (compare_for_stack_reg): Add bool argument.
	Detect FTST instruction and handle its register pops.  Only pop
	second operand if can_pop_second_op is true.
	(subst_stack_regs_pat) <case COMPARE>: Detect FCOMI instruction to
	set can_pop_second_op to false in the compare_for_stack_reg call.

	* config/i386/i386.md (*cmpi<FPCMP:unord><MODEF:mode>): Only call
	output_fp_compare for stack register operands.
	* config/i386/i386.c (output_fp_compare): Do not output SSE compare
	instructions here.  Do not emit stack register pops here.  Assert
	that FCOMPP pops next to top stack register.  Rewrite function.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@253821 138bc75d-0d04-0410-961f-82ee72b054a4