re PR tree-optimization/93118 (>>32<<32 is not always converted into &~0ffffffffull at the tree level)

	PR tree-optimization/93118
	* match.pd ((x >> c) << c -> x & (-1<<c)): Add nop_convert?.  Add new
	simplifier with two intermediate conversions.

	* gcc.dg/tree-ssa/pr93118.c: New test.

From-SVN: r279950