RAII auto_mpfr and autp_mpz

The following adds two RAII classes, one for mpz_t and one for mpfr_t
making object lifetime management easier.  Both formerly require
explicit initialization with {mpz,mpfr}_init and release with
{mpz,mpfr}_clear.

I've converted two example places (where lifetime is trivial).

	* system.h (class auto_mpz): New,
	* realmpfr.h (class auto_mpfr): Likewise.
	* fold-const-call.cc (do_mpfr_arg1): Use auto_mpfr.
	(do_mpfr_arg2): Likewise.
	* tree-ssa-loop-niter.cc (bound_difference): Use auto_mpz;

1 files changed, 18 insertions, 0 deletions

diff --git a/gcc/system.h b/gcc/system.h
index cf45db3..71d8a04 100644
--- a/gcc/system.h
+++ b/gcc/system.h
@@ -701,6 +701,24 @@ extern int vsnprintf (char *, size_t, const char *, va_list);
 /* Do not introduce a gmp.h dependency on the build system.  */
 #ifndef GENERATOR_FILE
 #include <gmp.h>
+
+class auto_mpz
+{
+public:
+  auto_mpz () { mpz_init (m_mpz); }
+  ~auto_mpz () { mpz_clear (m_mpz); }
+
+  operator mpz_t& () { return m_mpz; }
+
+  auto_mpz (const auto_mpz &) = delete;
+  auto_mpz &operator= (const auto_mpz &) = delete;
+
+  friend void mpz_clear (auto_mpz&) = delete;
+  friend void mpz_init (auto_mpz&) = delete;
+
+private:
+  mpz_t m_mpz;
+};
 #endif
 
 /* Get libiberty declarations.  */