x86: Also handle all 1s float vector constant

x86: Also handle all 1s float vector constant

Since float vector constant

(const_vector:V4SF [(const_double:SF -QNaN [-QNaN]) repeated x4])

is an all 1s float vector constant, update the remove_redundant_vector
pass to replace

(insn 20 18 21 2 (set (reg:V4SF 124)
        (const_vector:V4SF [
                (const_double:SF -QNaN [-QNaN]) repeated x4
            ])) "x.cc":26:5 2426 {movv4sf_internal}
     (nil))

with

(insn 49 2 5 2 (set (reg:V16QI 135)
        (const_vector:V16QI [
                (const_int -1 [0xffffffffffffffff]) repeated x16
            ])) -1
     (nil))
...
(insn 20 18 21 2 (set (reg:V4SF 124)
        (subreg:V4SF (reg:V16QI 135) 0)) "x.cc":26:5 2426 {movv4sf_internal}
     (nil))

gcc/

	PR target/120819
	* config/i386/i386-features.cc (ix86_broadcast_inner): Also handle
	all 1s float vector constant.

gcc/testsuite/

	PR target/120819
	* g++.target/i386/pr120819.C: New test.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>