re PR tree-optimization/89143 (comparison of abs(i) against excessive constant…

re PR tree-optimization/89143 (comparison of abs(i) against excessive constant less than UXXX_MAX no longer folded)

	PR tree-optimization/89143
	* wide-int-range.h (wide_int_range_absu): Declare.
	* wide-int-range.cc (wide_int_range_absu): New function.
	* tree-vrp.c (extract_range_from_unary_expr): Handle ABSU_EXPR.

	* gcc.dg/tree-ssa/vrp121.c: New test.

From-SVN: r268445

gcc/ChangeLog

 2019-02-01  Jakub Jelinek  <jakub@redhat.com>
 
+	PR tree-optimization/89143
+	* wide-int-range.h (wide_int_range_absu): Declare.
+	* wide-int-range.cc (wide_int_range_absu): New function.
+	* tree-vrp.c (extract_range_from_unary_expr): Handle ABSU_EXPR.
+
 	PR tree-optimization/88107
 	* tree-cfg.c (find_outermost_region_in_block): Add ALL argument,
 	instead of assertion that eh_region_outermost is non-NULL, if it

gcc/testsuite/ChangeLog

 2019-02-01  Jakub Jelinek  <jakub@redhat.com>
 
+	PR tree-optimization/89143
+	* gcc.dg/tree-ssa/vrp121.c: New test.
+
 	PR tree-optimization/88107
 	* gcc.dg/gomp/pr88107.c: New test.
 

gcc/testsuite/gcc.dg/tree-ssa/vrp121.c

+/* PR tree-optimization/89143 */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+/* { dg-final { scan-tree-dump-not "link_error \\\(" "optimized" } } */
+
+void link_error (void);
+
+void
+f1 (signed char i)
+{
+  if (__builtin_abs (i) < 0 || __builtin_abs (i) > __SCHAR_MAX__ + 1)
+    link_error ();
+}
+
+void
+f2 (signed char i)
+{
+  if (i < 0 || i > 15)
+    __builtin_unreachable ();
+  if (__builtin_abs (i) < 0 || __builtin_abs (i) > 15)
+    link_error ();
+}
+
+void
+f3 (signed char i)
+{
+  if (i < 19 || i > 25)
+    __builtin_unreachable ();
+  if (__builtin_abs (i) < 19 || __builtin_abs (i) > 25)
+    link_error ();
+}
+
+void
+f4 (signed char i)
+{
+  if (i > -60)
+    __builtin_unreachable ();
+  if (__builtin_abs (i) < 60 || __builtin_abs (i) > __SCHAR_MAX__ + 1)
+    link_error ();
+}
+
+void
+f5 (signed char i)
+{
+  if (i < -__SCHAR_MAX__ || i > -30)
+    __builtin_unreachable ();
+  if (__builtin_abs (i) < 30 || __builtin_abs (i) > __SCHAR_MAX__)
+    link_error ();
+}
+
+void
+f6 (signed char i)
+{
+  if (i < -__SCHAR_MAX__ || i > 30)
+    __builtin_unreachable ();
+  if (__builtin_abs (i) < 0 || __builtin_abs (i) > __SCHAR_MAX__)
+    link_error ();
+}
+
+void
+f7 (signed char i)
+{
+  if (i < -31 || i > 30)
+    __builtin_unreachable ();
+  if (__builtin_abs (i) < 0 || __builtin_abs (i) > 31)
+    link_error ();
+}

gcc/tree-vrp.c

@@ -2196,6 +2196,16 @@ extract_range_from_unary_expr (value_range_base *vr,
 	vr->set_varying ();
       return;
     }
+  else if (code == ABSU_EXPR)
+    {
+      wide_int wmin, wmax;
+      wide_int vr0_min, vr0_max;
+      extract_range_into_wide_ints (&vr0, SIGNED, prec, vr0_min, vr0_max);
+      wide_int_range_absu (wmin, wmax, prec, vr0_min, vr0_max);
+      vr->set (VR_RANGE, wide_int_to_tree (type, wmin),
+	       wide_int_to_tree (type, wmax));
+      return;
+    }
 
   /* For unhandled operations fall back to varying.  */
   vr->set_varying ();

gcc/wide-int-range.cc

@@ -735,6 +735,37 @@ wide_int_range_abs (wide_int &min, wide_int &max,
   return true;
 }
 
+/* Calculate ABSU_EXPR on a range and store the result in [MIN, MAX].  */
+
+void
+wide_int_range_absu (wide_int &min, wide_int &max,
+		     unsigned prec, const wide_int &vr0_min,
+		     const wide_int &vr0_max)
+{
+  /* Pass through VR0 the easy cases.  */
+  if (wi::ges_p (vr0_min, 0))
+    {
+      min = vr0_min;
+      max = vr0_max;
+      return;
+    }
+
+  min = wi::abs (vr0_min);
+  max = wi::abs (vr0_max);
+
+  /* If the range contains zero then we know that the minimum value in the
+     range will be zero.  */
+  if (wi::ges_p (vr0_max, 0))
+    {
+      if (wi::gtu_p (min, max))
+	max = min;
+      min = wi::zero (prec);
+    }
+  else
+    /* Otherwise, swap MIN and MAX.  */
+    std::swap (min, max);
+}
+
 /* Convert range in [VR0_MIN, VR0_MAX] with INNER_SIGN and INNER_PREC,
    to a range in [MIN, MAX] with OUTER_SIGN and OUTER_PREC.
 

gcc/wide-int-range.h

@@ -107,6 +107,10 @@ extern bool wide_int_range_abs (wide_int &min, wide_int &max,
 				const wide_int &vr0_min,
 				const wide_int &vr0_max,
 				bool overflow_undefined);
+extern void wide_int_range_absu (wide_int &min, wide_int &max,
+				 unsigned prec,
+				 const wide_int &vr0_min,
+				 const wide_int &vr0_max);
 extern bool wide_int_range_convert (wide_int &min, wide_int &max,
 				    signop inner_sign,
 				    unsigned inner_prec,