2017-03-10  Olivier Hainque  <hainque@adacore.com>

	* tree-switch-conversion (array_value_type): Start by resetting
	candidate type to it's main variant.

	testsuite/
	* gnat.dg/opt64.adb: New test.
	* gnat.dg/opt64_pkg.ads: New helper.
	* gnat.dg/opt64_pkg.adb: New helper.

From-SVN: r246024