2009-08-18  Richard Guenther  <rguenther@suse.de>

	PR middle-end/41094
	* builtins.c (fold_builtin_pow): Fold pow(pow(x,y),z) to
	pow(x,y*z) only if x is nonnegative.

	* gcc.dg/torture/pr41094.c: New testcase.
	* gcc.dg/torture/builtin-power-1.c: Adjust.
	* gcc.dg/builtins-10.c: Likewise.

From-SVN: r150874