re PR middle-end/29335 (transcendental functions with constant arguments should be...

re PR middle-end/29335 (transcendental functions with constant arguments should be resolved at compile-time)

	PR middle-end/29335
	* builtins.c (do_mpfr_arg2, fold_builtin_hypot): New.
	(fold_builtin_pow): Evaluate constant arguments at compile-time
	using MPFR.
	(fold_builtin_1): Handle BUILT_IN_ATAN2 and BUILT_IN_HYPOT.
	(do_mpfr_ckconv): New helper function.
	(do_mpfr_arg1): Use do_mpfr_ckconv.
	(do_mpfr_arg2): New.

testsuite:
	* gcc.dg/builtins-20.c: Add tests for hypot.
	* gcc.dg/torture/builtin-math-2.c (TESTIT2): New.  Add tests for
	two-argument builtins.
	* gcc.dg/torture/builtin-math-3.c (TESTIT_R): Renamed from
	TESTIT2.  Update all callers.
	(TESTIT2, TESTIT2_R): New helper macros.
	Add testcases for pow, hypot and atan2.

From-SVN: r118129