frange: drop endpoints to min/max representable numbers for -ffinite-math-only.

Similarly to how we drop NANs to UNDEFINED when -ffinite-math-only, I
think we can drop the numbers outside of the min/max representable
numbers to the representable number.

This means the endpoings to VR_VARYING for -ffinite-math-only can now
be the min/max representable, instead of -INF and +INF.

Saturating in the setter means that the upcoming implementation for
binary operators no longer have to worry about doing the right
thing for -ffinite-math-only.  If the range goes outside the limits,
it'll get chopped down.

Tested on x86-64 Linux.

gcc/ChangeLog:

	* range-op-float.cc (build_le): Use vrp_val_*.
	(build_lt): Same.
	(build_ge): Same.
	(build_gt): Same.
	* value-range.cc (frange::set): Chop ranges outside of the
	representable numbers for -ffinite-math-only.
	(frange::normalize_kind): Use vrp_val*.
	(frange::verify_range): Same.
	(frange::set_nonnegative): Same.
	(range_tests_floats): Remove tests that depend on -INF and +INF.
	* value-range.h (real_max_representable): Add prototype.
	(real_min_representable): Same.
	(vrp_val_max): Set max representable number for
	-ffinite-math-only.
	(vrp_val_min): Same but for min.
	(frange::set_varying): Use vrp_val*.

1 files changed, 63 insertions, 12 deletions

diff --git a/gcc/value-range.h b/gcc/value-range.h
index 3668b33..413e54b 100644
--- a/gcc/value-range.h
+++ b/gcc/value-range.h
@@ -593,6 +593,8 @@ extern void dump_value_range (FILE *, const vrange *);
 extern bool vrp_val_is_min (const_tree);
 extern bool vrp_val_is_max (const_tree);
 extern bool vrp_operand_equal_p (const_tree, const_tree);
+inline REAL_VALUE_TYPE frange_val_min (const_tree type);
+inline REAL_VALUE_TYPE frange_val_max (const_tree type);
 
 inline value_range_kind
 vrange::kind () const
@@ -1009,7 +1011,10 @@ vrp_val_max (const_tree type)
       return wide_int_to_tree (const_cast<tree> (type), max);
     }
   if (frange::supports_p (type))
-    return build_real (const_cast <tree> (type), dconstinf);
+    {
+      REAL_VALUE_TYPE r = frange_val_max (type);
+      return build_real (const_cast <tree> (type), r);
+    }
   return NULL_TREE;
 }
 
@@ -1023,7 +1028,10 @@ vrp_val_min (const_tree type)
   if (POINTER_TYPE_P (type))
     return build_zero_cst (const_cast<tree> (type));
   if (frange::supports_p (type))
-    return build_real (const_cast <tree> (type), dconstninf);
+    {
+      REAL_VALUE_TYPE r = frange_val_min (type);
+      return build_real (const_cast <tree> (type), r);
+    }
   return NULL_TREE;
 }
 
@@ -1073,8 +1081,8 @@ frange::set_varying (tree type)
 {
   m_kind = VR_VARYING;
   m_type = type;
-  m_min = dconstninf;
-  m_max = dconstinf;
+  m_min = frange_val_min (type);
+  m_max = frange_val_max (type);
   m_pos_nan = true;
   m_neg_nan = true;
 }
@@ -1132,23 +1140,66 @@ frange::clear_nan ()
 
 // Set R to maximum representable value for TYPE.
 
-inline void
-real_max_representable (REAL_VALUE_TYPE *r, tree type)
+inline REAL_VALUE_TYPE
+real_max_representable (const_tree type)
 {
+  REAL_VALUE_TYPE r;
   char buf[128];
   get_max_float (REAL_MODE_FORMAT (TYPE_MODE (type)),
 		 buf, sizeof (buf), false);
-  int res = real_from_string (r, buf);
+  int res = real_from_string (&r, buf);
   gcc_checking_assert (!res);
+  return r;
 }
 
-// Set R to minimum representable value for TYPE.
+// Return the minimum representable value for TYPE.
 
-inline void
-real_min_representable (REAL_VALUE_TYPE *r, tree type)
+inline REAL_VALUE_TYPE
+real_min_representable (const_tree type)
+{
+  REAL_VALUE_TYPE r = real_max_representable (type);
+  r = real_value_negate (&r);
+  return r;
+}
+
+// Return the minimum value for TYPE.
+
+inline REAL_VALUE_TYPE
+frange_val_min (const_tree type)
+{
+  if (flag_finite_math_only)
+    return real_min_representable (type);
+  else
+    return dconstninf;
+}
+
+// Return the maximum value for TYPE.
+
+inline REAL_VALUE_TYPE
+frange_val_max (const_tree type)
+{
+  if (flag_finite_math_only)
+    return real_max_representable (type);
+  else
+    return dconstinf;
+}
+
+// Return TRUE if R is the minimum value for TYPE.
+
+inline bool
+frange_val_is_min (const REAL_VALUE_TYPE &r, const_tree type)
+{
+  REAL_VALUE_TYPE min = frange_val_min (type);
+  return real_identical (&min, &r);
+}
+
+// Return TRUE if R is the max value for TYPE.
+
+inline bool
+frange_val_is_max (const REAL_VALUE_TYPE &r, const_tree type)
 {
-  real_max_representable (r, type);
-  *r = real_value_negate (r);
+  REAL_VALUE_TYPE max = frange_val_max (type);
+  return real_identical (&max, &r);
 }
 
 // Build a signless NAN of type TYPE.