i386: Roundeven expansion for SSE4.1+

i386: Roundeven expansion for SSE4.1+

gcc/ChangeLog:

2019-08-26  Tejas Joshi  <tejasjoshi9673@gmail.com>
            Uros Bizjak  <ubizjak@gmail.com>

	* builtins.c (mathfn_built_in_2): Change CASE_MATHFN to
	CASE_MATHFN_FLOATN for roundeven.
	* config/i386/i386.c (ix86_i387_mode_needed): Add case
	I387_ROUNDEVEN.
	(ix86_mode_needed): Likewise.
	(ix86_mode_after): Likewise.
	(ix86_mode_entry): Likewise.
	(ix86_mode_exit): Likewise.
	(ix86_emit_mode_set): Likewise.
	(emit_i387_cw_initialization): Add case I387_CW_ROUNDEVEN.
	* config/i386/i386.h (ix86_stack_slot): Add SLOT_CW_ROUNDEVEN.
	(ix86_entry): Add I387_ROUNDEVEN.
	(avx_u128_state): Add I387_CW_ANY.
	* config/i386/i386.md: Define UNSPEC_FRNDINT_ROUNDEVEN.
	(define_int_iterator): Likewise.
	(define_int_attr): Likewise for rounding_insn, rounding and ROUNDING.
	(define_constant): Define ROUND_ROUNDEVEN mode.
	(define_attr): Add roundeven mode for i387_cw.
	(<rouding_insn><mode>2): Add condition for ROUND_ROUNDEVEN.
	* internal-fn.def (ROUNDEVEN): New builtin function.
	* optabs.def (roundeven_optab): New optab.

gcc/testsuite/ChangeLog:

2019-08-26  Tejas Joshi  <tejasjoshi9673@gmail.com>

	* gcc.target/i386/sse4_1-round-roundeven-1.c: New test.
	* gcc.target/i386/sse4_1-round-roundeven-2.c: New test.

Co-Authored-By: Uros Bizjak <ubizjak@gmail.com>
From-SVN: r274928