fold-const.c (fold_strip_sign_ops): New function to simplify a floating point expression ignoring the sign of the...


	* fold-const.c (fold_strip_sign_ops): New function to simplify a
	floating point expression ignoring the sign of the result.
	(fold) <ABS_EXPR>: Use it to simplify fabs(x).
	(fold) <MULT_EXPR>: Use it to simplify x*x.
	* tree.h (fold_strip_sign_ops): Prototype here.
	* builtins.c (fold_builtin_copysign): Take an additional FNDECL
	argument.  Use fold_strip_sign_ops to simplify the first argument.
	(fold_builtin_pow):  Use fold_strip_sign_ops to simplify the
	first argument when the second argument is an even integer
	constant, but only with -funsafe_math_optimizations.
	(fold_builtin_1): Update call to fold_builtin_copysign.

	* gcc.dg/builtins-48.c: New test case.
	* gcc.dg/builtins-49.c: New test case.
	* gcc.dg/builtins-50.c: New test case.
	* gcc.dg/builtins-51.c: New test case.

From-SVN: r94779