[committed] Fix VRP range meet (PR tree-optimization/59358)

[Jakub Jelinek]

Hi!

The following testcase is miscompiled (to endless loop), because
union_ranges didn't count with the possibility that *vr0max and vr1max
are uncomparable (one of them is symbolic).

Fixed thusly, bootstrapped/regtested on x86_64-linux and i686-linux,
preapproved by richi on IRC, committed to trunk/4.8.

2013-12-02  Jakub Jelinek  <ja...@redhat.com>

        PR tree-optimization/59358
        * tree-vrp.c (union_ranges): To check for the partially
        overlapping ranges or adjacent ranges, also compare *vr0max
        with vr1max.

        * gcc.c-torture/execute/pr59358.c: New test.

--- gcc/tree-vrp.c.jj   2013-11-28 23:51:58.000000000 +0100
+++ gcc/tree-vrp.c      2013-12-02 13:24:10.750956769 +0100
@@ -7758,7 +7758,8 @@ union_ranges (enum value_range_type *vr0
     }
   else if ((operand_less_p (vr1min, *vr0max) == 1
            || operand_equal_p (vr1min, *vr0max, 0))
-          && operand_less_p (*vr0min, vr1min) == 1)
+          && operand_less_p (*vr0min, vr1min) == 1
+          && operand_less_p (*vr0max, vr1max) == 1)
     {
       /* [  (  ]  ) or [   ](   ) */
       if (*vr0type == VR_RANGE
@@ -7792,7 +7793,8 @@ union_ranges (enum value_range_type *vr0
     }
   else if ((operand_less_p (*vr0min, vr1max) == 1
            || operand_equal_p (*vr0min, vr1max, 0))
-          && operand_less_p (vr1min, *vr0min) == 1)
+          && operand_less_p (vr1min, *vr0min) == 1
+          && operand_less_p (vr1max, *vr0max) == 1)
     {
       /* (  [  )  ] or (   )[   ] */
       if (*vr0type == VR_RANGE
--- gcc/testsuite/gcc.c-torture/execute/pr59358.c.jj    2013-12-02 
13:26:33.984198815 +0100
+++ gcc/testsuite/gcc.c-torture/execute/pr59358.c       2013-12-02 
13:26:17.000000000 +0100
@@ -0,0 +1,44 @@
+/* PR tree-optimization/59358 */
+
+__attribute__((noinline, noclone)) int
+foo (int *x, int y)
+{
+  int z = *x;
+  if (y > z && y <= 16)
+    while (y > z)
+      z *= 2;
+  return z;
+}
+
+int
+main ()
+{
+  int i;
+  for (i = 1; i < 17; i++)
+    {
+      int j = foo (&i, 16);
+      int k;
+      if (i >= 8 && i <= 15)
+       k = 16 + (i - 8) * 2;
+      else if (i >= 4 && i <= 7)
+       k = 16 + (i - 4) * 4;
+      else if (i == 3)
+       k = 24;
+      else
+       k = 16;
+      if (j != k)
+       __builtin_abort ();
+      j = foo (&i, 7);
+      if (i >= 7)
+       k = i;
+      else if (i >= 4)
+       k = 8 + (i - 4) * 2;
+      else if (i == 3)
+       k = 12;
+      else
+       k = 8;
+      if (j != k)
+       __builtin_abort ();
+    }
+  return 0;
+}

        Jakub