re PR c++/78655 (gcc doesn't exploit the fact that the result of pointer addition...

2018-08-20  Richard Biener  <rguenther@suse.de>

	PR tree-optimization/78655
	* tree-vrp.c (extract_range_from_binary_expr_1): Make
	pointer + offset nonnull if either operand is nonnull work.

	* gcc.dg/tree-ssa/evrp11.c: New testcase.

From-SVN: r263662

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 3dbcd1c..6cf673c 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2018-08-20  Richard Biener  <rguenther@suse.de>
+
+       PR tree-optimization/78655
+       * tree-vrp.c (extract_range_from_binary_expr_1): Make
+       pointer + offset nonnull if either operand is nonnull work.
+
 2018-08-20  Tom de Vries  <tdevries@suse.de>
 
        * dwarf2out.c (add_scalar_info): Don't add reference to existing die

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index e89f4a4..1eaec90 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2018-08-20  Richard Biener  <rguenther@suse.de>
+
+       PR tree-optimization/78655
+       * gcc.dg/tree-ssa/evrp11.c: New testcase.
+
 2018-08-18  Iain Sandoe  <iain@sandoe.co.uk>
 
        * gcc.dg/debug/dwarf2/pr80263.c: Suppress pubtypes output

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/evrp11.c b/gcc/testsuite/gcc.dg/tree-ssa/evrp11.c
new file mode 100644 (file)
index 0000000..f1373bd
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/evrp11.c
@@ -0,0 +1,23 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-evrp" } */
+
+extern void link_error ();
+
+void foo (int *x)
+{
+  int *p = x + 1;
+  if (p == 0)
+    link_error ();
+}
+
+void bar (char *x, int a)
+{
+  if (a != 0)
+    {
+      char *p = x + a;
+      if (p == 0)
+       link_error ();
+    }
+}
+
+/* { dg-final { scan-tree-dump-not "link_error" "evrp" } }  */

diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c
index d553a25..2ddb0c2 100644 (file)
--- a/gcc/tree-vrp.c
+++ b/gcc/tree-vrp.c
@@ -1437,6 +1437,7 @@ extract_range_from_binary_expr_1 (value_range *vr,
       && code != PLUS_EXPR
       && code != MINUS_EXPR
       && code != RSHIFT_EXPR
+      && code != POINTER_PLUS_EXPR
       && (vr0.type == VR_VARYING
          || vr1.type == VR_VARYING
          || vr0.type != vr1.type
@@ -1467,7 +1468,11 @@ extract_range_from_binary_expr_1 (value_range *vr,
        {
          /* For pointer types, we are really only interested in asserting
             whether the expression evaluates to non-NULL.  */
-         if (range_is_nonnull (&vr0) || range_is_nonnull (&vr1))
+         if (range_is_nonnull (&vr0)
+             || range_is_nonnull (&vr1)
+             || (vr1.type == VR_RANGE
+                 && !symbolic_range_p (&vr1)
+                 && !range_includes_zero_p (vr1.min, vr1.max)))
            set_value_range_to_nonnull (vr, expr_type);
          else if (range_is_null (&vr0) && range_is_null (&vr1))
            set_value_range_to_null (vr, expr_type);