re PR target/30652 (SSE expansion is missing for isinf() and other fpclassify functions)

	PR target/30652
	PR middle-end/20558

	* builtins.c (expand_builtin_interclass_mathfn): Provide a
	generic fallback for isinf.
	* c-cppbuiltin.c (builtin_define_float_constants): Move FP max
	calculation code ...
	* real.c (get_max_float): ... to here.
	* real.h (get_max_float): New.

testsuite:
	* gcc.dg/pr28796-1.c: Add more cases.
	* gcc.dg/pr28796-2.c: Likewise.

From-SVN: r126724

1 files changed, 32 insertions, 0 deletions

diff --git a/gcc/real.c b/gcc/real.c
index b4d617f94d6..258ecf6635b 100644
--- a/gcc/real.c
+++ b/gcc/real.c
@@ -4835,3 +4835,35 @@ real_isinteger (const REAL_VALUE_TYPE *c, enum machine_mode mode)
   real_trunc (&cint, mode, c);
   return real_identical (c, &cint);
 }
+
+/* Write into BUF the maximum representable finite floating-point
+   number, (1 - b**-p) * b**emax for a given FP format FMT as a hex
+   float string.  LEN is the size of BUF, and the buffer must be large
+   enough to contain the resulting string.  */
+
+void
+get_max_float (const struct real_format *fmt, char *buf, size_t len)
+{
+  int i, n;
+  char *p;
+
+  strcpy (buf, "0x0.");
+  n = fmt->p;
+  for (i = 0, p = buf + 4; i + 3 < n; i += 4)
+    *p++ = 'f';
+  if (i < n)
+    *p++ = "08ce"[n - i];
+  sprintf (p, "p%d", fmt->emax);
+  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];
+    }
+
+  gcc_assert (strlen (buf) < len);
+}