Backported from mainline

	Backported from mainline
	2013-01-28  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/56125
	* tree-ssa-math-opts.c (gimple_expand_builtin_pow): Don't optimize
	pow(x,c) into sqrt(x) * powi(x, n/2) or
	1.0 / (sqrt(x) * powi(x, abs(n/2))) if c is an integer or when
	optimizing for size.
	Don't optimize pow(x,c) into powi(x, n/3) * powi(cbrt(x), n%3) or
	1.0 / (powi(x, abs(n)/3) * powi(cbrt(x), abs(n)%3)) if 2c is an
	integer.

	* gcc.dg/pr56125.c: New test.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/gcc-4_7-branch@195664 138bc75d-0d04-0410-961f-82ee72b054a4