[PATCH] Add global REAL_VALUE_TYPE infinities to real.*.

[Aldy Hernandez via Gcc-patches]

We're starting to abuse the infinity endpoints in the frange code and
the associated range operators.  Building infinities are rather cheap,
and we could even inline them, but I think it's best to just not
recalculate them all the time.

I see about 20 uses of real_inf in the source code, not including the
backends.  And I'm about to add more :).

OK pending tests?

gcc/ChangeLog:

        * emit-rtl.cc (init_emit_once): Initialize dconstinf and
        dconstninf.
        * real.h: Add dconstinf and dconstninf.
---
 gcc/emit-rtl.cc | 5 +++++
 gcc/real.h      | 2 ++
 2 files changed, 7 insertions(+)

diff --git a/gcc/emit-rtl.cc b/gcc/emit-rtl.cc
index 3929ee08986..f25fb70ab97 100644
--- a/gcc/emit-rtl.cc
+++ b/gcc/emit-rtl.cc
@@ -107,6 +107,8 @@ REAL_VALUE_TYPE dconst1;
 REAL_VALUE_TYPE dconst2;
 REAL_VALUE_TYPE dconstm1;
 REAL_VALUE_TYPE dconsthalf;
+REAL_VALUE_TYPE dconstinf;
+REAL_VALUE_TYPE dconstninf;
 
 /* Record fixed-point constant 0 and 1.  */
 FIXED_VALUE_TYPE fconst0[MAX_FCONST0];
@@ -6210,6 +6212,9 @@ init_emit_once (void)
   dconsthalf = dconst1;
   SET_REAL_EXP (&dconsthalf, REAL_EXP (&dconsthalf) - 1);
 
+  real_inf (&dconstinf);
+  real_inf (&dconstninf, true);
+
   for (i = 0; i < 3; i++)
     {
       const REAL_VALUE_TYPE *const r =
diff --git a/gcc/real.h b/gcc/real.h
index ec78e8a8932..2f490ef9b72 100644
--- a/gcc/real.h
+++ b/gcc/real.h
@@ -462,6 +462,8 @@ extern REAL_VALUE_TYPE dconst1;
 extern REAL_VALUE_TYPE dconst2;
 extern REAL_VALUE_TYPE dconstm1;
 extern REAL_VALUE_TYPE dconsthalf;
+extern REAL_VALUE_TYPE dconstinf;
+extern REAL_VALUE_TYPE dconstninf;
 
 #define dconst_e() (*dconst_e_ptr ())
 #define dconst_third() (*dconst_third_ptr ())
-- 
2.37.1