slp: remove unneeded permute calculation (PR99656)

slp: remove unneeded permute calculation (PR99656)

The attach testcase ICEs because as you showed on the PR we have one child
which is an internal with a PERM of EVENEVEN and one with TOP.

The problem is while we can conceptually merge the permute itself into EVENEVEN,
merging the lanes don't really make sense.

That said, we no longer even require the merged lanes as we create the permutes
based on the KIND directly.

This patch just removes all of that code.

Unfortunately it still won't vectorize with the cost model enabled due to the
blend that's created combining the load and the external

	note: node 0x51f2ce8 (max_nunits=1, refcnt=1)
	note: op: VEC_PERM_EXPR
	note:       { }
	note:       lane permutation { 0[0] 1[1] }
	note:       children 0x51f23e0 0x51f2578
	note: node 0x51f23e0 (max_nunits=2, refcnt=1)
	note: op template: _16 = REALPART_EXPR <*t1_9(D)>;
	note:       stmt 0 _16 = REALPART_EXPR <*t1_9(D)>;
	note:       stmt 1 _16 = REALPART_EXPR <*t1_9(D)>;
	note:       load permutation { 0 0 }
	note: node (external) 0x51f2578 (max_nunits=1, refcnt=1)
	note:       { _18, _18 }

which costs the cost for the load-and-split and the cost of the external splat,
and the one for blending them while in reality it's just a scalar load and
insert.

The compiler (with the cost model disabled) generates

	ldr     q1, [x19]
	dup     v1.2d, v1.d[0]
	ldr     d0, [x19, 8]
	fneg    d0, d0
	ins     v1.d[1], v0.d[0]

while really it should be

	ldp     d1, d0, [x19]
	fneg    d0, d0
	ins     v1.d[1], v0.d[0]

but that's for another time.

gcc/ChangeLog:

	PR tree-optimization/99656
	* tree-vect-slp-patterns.c (linear_loads_p,
	complex_add_pattern::matches, is_eq_or_top,
	vect_validate_multiplication, complex_mul_pattern::matches,
	complex_fms_pattern::matches): Remove complex_perm_kinds_t.
	* tree-vectorizer.h: (complex_load_perm_t): Removed.
	(slp_tree_to_load_perm_map_t): Use complex_perm_kinds_t instead of
	complex_load_perm_t.

gcc/testsuite/ChangeLog:

	PR tree-optimization/99656
	* gfortran.dg/vect/pr99656.f90: New test.