real.c (encode_ibm_extended): Don't bother rounding low double.

	* real.c (encode_ibm_extended): Don't bother rounding low double.
	* c-cppbuiltin.c (builtin_define_float_constants): Tweak MAX
	when fmt->pnan < fmt->p.

From-SVN: r78900

gcc/ChangeLog

+2004-03-04  Alan Modra  <amodra@bigpond.net.au>
+
+	* real.c (encode_ibm_extended): Don't bother rounding low double.
+	* c-cppbuiltin.c (builtin_define_float_constants): Tweak MAX
+	when fmt->pnan < fmt->p.
+
 2004-03-04  Eric Christopher  <echristo@redhat.com>
 
 	* config/mips/mips.h (FUNCTION_ARG_REGNO_P): Fix to check

gcc/c-cppbuiltin.c

@@ -193,6 +193,16 @@ builtin_define_float_constants (const char *name_prefix, const char *fp_suffix,
     if (i < n)
       *p++ = "08ce"[n - i];
     sprintf (p, "p%d", fmt->emax * fmt->log2_b);
+    if (fmt->pnan < fmt->p)
+      {
+	/* This is an IBM extended double format made up of two IEEE
+	   doubles.  The value of the long double is the sum of the
+	   values of the two parts.  The most significant part is
+	   required to be the value of the long double rounded to the
+	   nearest double.  Rounding means we need a slightly smaller
+	   value for LDBL_MAX.  */
+	buf[4 + fmt->pnan / 4] = "7bde"[fmt->pnan % 4];
+      }
   }
   sprintf (name, "__%s_MAX__", name_prefix);
   builtin_define_with_hex_fp_value (name, type, decimal_dig, buf, fp_suffix);

gcc/real.c

@@ -3248,7 +3248,9 @@ encode_ibm_extended (const struct real_format *fmt, long *buf,
   if (u.class == rvc_normal)
     {
       do_add (&v, &normr, &u, 1);
-      round_for_format (base_fmt, &v);
+      /* The low double won't need rounding, since we round to a 106 bit
+	 mantissa before calling this function, and we've just
+	 subtracted off the top 54 bits.  (53+1 because u is rounded.)  */
       encode_ieee_double (base_fmt, &buf[2], &v);
     }
   else