PR optimization/10817

	PR optimization/10817
	* ifcvt.c (noce_emit_move_insn): Improve documentation comment.
	(noce_try_move): New function to optimize an if-the-else into an
	unconditional move, i.e. "if (a!=b) x=a; else x=b" into "x=a".
	(noce_process_if_block): Attempt simplification with noce_try_move.

	* simplify-rtx.c (simplify_ternary_operation): Some minor fixes
	and improvements to the optimizations of IF_THEN_ELSE expressions.
	(simplify_subreg): Silence signed/unsigned comparison warning.

	* gcc.c-torture/compile/20031102-1.c: New test case.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@73200 138bc75d-0d04-0410-961f-82ee72b054a4