The failures in this PR were from forcing { dg-do run } even when
vect.exp chooses options that are incompatible with the runtime.
The default vect.exp behaviour is to execute when possible, so there's
no need for a dg-do at all.

The patch removes other unconditional { dg-do run }s too.  Many of them
were already failing in the same way.

Also, the dg-do run condition in vect-reduc-or* seems unnecessary:
the test should run correctly whatever happens, and the scan tests
are already guarded properly.

2018-01-24  Richard Sandiford  <richard.sandiford@linaro.org>

gcc/testsuite/
	PR testsuite/83889
	* gcc.dg/vect/pr79920.c: Remove explicit dg-do run.
	* gcc.dg/vect/pr80631-1.c: Likewise.
	* gcc.dg/vect/pr80631-2.c: Likewise.
	* gcc.dg/vect/pr81410.c: Likewise.
	* gcc.dg/vect/pr81633.c: Likewise.
	* gcc.dg/vect/pr81815.c: Likewise.
	* gcc.dg/vect/pr82108.c: Likewise.
	* gcc.dg/vect/pr83857.c: Likewise.
	* gcc.dg/vect/vect-alias-check-8.c: Likewise.
	* gcc.dg/vect/vect-alias-check-9.c: Likewise.
	* gcc.dg/vect/vect-alias-check-10.c: Likewise.
	* gcc.dg/vect/vect-alias-check-11.c: Likewise.
	* gcc.dg/vect/vect-alias-check-12.c: Likewise.
	* gcc.dg/vect/vect-reduc-11.c: Likewise.
	* gcc.dg/vect/vect-tail-nomask-1.c: Likewise.
	* gcc.dg/vect/vect-reduc-in-order-1.c: Remove dg-do run and use
	dg-xfail-run-if instead.
	* gcc.dg/vect/vect-reduc-in-order-2.c: Likewise.
	* gcc.dg/vect/vect-reduc-in-order-3.c: Likewise.
	* gcc.dg/vect/vect-reduc-in-order-4.c: Likewise.
	* gcc.dg/vect/vect-reduc-or_1.c: Remove conditional dg-do run.
	* gcc.dg/vect/vect-reduc-or_2.c: Likewise.

From-SVN: r257022