re PR middle-end/29335 (transcendental functions with constant arguments should be resolved at compile-time)
PR middle-end/29335
* builtins.c (fold_builtin_cbrt, fold_builtin_logarithm):
Calculate compile-time constants using MPFR.
(fold_builtin_1): Likewise handle BUILT_IN_ERF, BUILT_IN_ERFC,
BUILT_IN_EXPM1 and BUILT_IN_LOG1P.
testsuite:
* gcc.dg/torture/builtin-math-2.c (TESTIT): Use new helper macro.
Add checks for log, log2, log10 and log1p.
* gcc.dg/torture/builtin-math-3.c: Add checks for -0.0 everywhere
we already test 0.0. Add checks for expm1, log, log2, log10,
log1p, cbrt, erf and erfc.