i386: Fix move costs in vectorizer cost model.

i386: Fix move costs in vectorizer cost model.

This patch complements the change to stv and uses COSTS_N_INSNS (...)/2
to convert move costs to COSTS_N_INSNS based costs used by vectorizer.
The patch makes pr9981 to XPASS so I removed xfail but it also makes
pr91446 fail.  This is about SLP

/* { dg-options "-O2 -march=icelake-server -ftree-slp-vectorize -mtune-ctrl=^sse_typeless_stores" } */

typedef struct
{
  unsigned long long width, height;
  long long x, y;
} info;

extern void bar (info *);

void
foo (unsigned long long width, unsigned long long height,
     long long x, long long y)
{
  info t;
  t.width = width;
  t.height = height;
  t.x = x;
  t.y = y;
  bar (&t);
}

/* { dg-final { scan-assembler-times "vmovdqa\[^\n\r\]*xmm\[0-9\]" 2 } } */

With fixed cost the construction cost is now too large so vectorization does
not happen.  This is the hack increasing cost to account integer->sse move which
I think we can handle incrementally.

gcc/ChangeLog:

	* config/i386/i386.cc (ix86_widen_mult_cost): Use sse_op to cost
	SSE integer addition.
	(ix86_multiplication_cost): Use COSTS_N_INSNS (...)/2 to cost sse
	loads.
	(ix86_shift_rotate_cost): Likewise.
	(ix86_vector_costs::add_stmt_cost): Likewise.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/pr91446.c: xfail.
	* gcc.target/i386/pr99881.c: remove xfail.