tree-ssa-alias.c (collect_points_to_info_r): Handle pointing to PTR + OFFSET as PTR...

	* tree-ssa-alias.c (collect_points_to_info_r): Handle
	pointing to PTR + OFFSET as PTR, not as pointing to PTR or pointing
	to OFFSET.

	* gcc.dg/tree-ssa/20040911-1.c: New test.

From-SVN: r87357

gcc/ChangeLog

+2004-09-11  Jakub Jelinek  <jakub@redhat.com>
+
+	* tree-ssa-alias.c (collect_points_to_info_r): Handle
+	pointing to PTR + OFFSET as PTR, not as pointing to PTR or pointing
+	to OFFSET.
+
 2004-09-11  Richard Henderson  <rth@redhat.com>
 
 	* expr.c (expand_expr_addr_expr_1) Rename from expand_expr_addr_expr.

gcc/testsuite/ChangeLog

+2004-09-11  Jakub Jelinek  <jakub@redhat.com>
+
+	* gcc.dg/tree-ssa/20040911-1.c: New test.
+
 2004-09-11  Andreas Jaeger  <aj@suse.de>
 
 	* gcc.c-torture/execute/991118-1.x: Delete, PR 16437 is fixed.

gcc/testsuite/gcc.dg/tree-ssa/20040911-1.c

+/* Verify that points-to information is handled properly for PTR + OFFSET
+   pointer arithmetics.  */
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-alias1-vops" } */
+
+char buf[4], *q;
+int foo (int i)
+{
+  char c, *p;
+  q = &c;
+  p = buf;
+  if (i)
+    p = p + 3;
+  else
+    p = p + 2;
+  *p = 6;
+  c = 8;
+  return *p;
+}
+
+/* { dg-final { scan-tree-dump-not "VUSE <c" "alias1" } } */

gcc/tree-ssa-alias.c

@@ -1869,7 +1869,8 @@ collect_points_to_info_r (tree var, tree stmt, void *data)
 	    
 	    /* Both operands may be of pointer type.  FIXME: Shouldn't
 	       we just expect PTR + OFFSET always?  */
-	    if (POINTER_TYPE_P (TREE_TYPE (op0)))
+	    if (POINTER_TYPE_P (TREE_TYPE (op0))
+		&& TREE_CODE (op0) != INTEGER_CST)
 	      {
 		if (TREE_CODE (op0) == SSA_NAME)
 		  merge_pointed_to_info (ai, var, op0);
@@ -1879,7 +1880,8 @@ collect_points_to_info_r (tree var, tree stmt, void *data)
 		  add_pointed_to_expr (var, op0);
 	      }
 
-	    if (POINTER_TYPE_P (TREE_TYPE (op1)))
+	    if (POINTER_TYPE_P (TREE_TYPE (op1))
+		&& TREE_CODE (op1) != INTEGER_CST)
 	      {
 		if (TREE_CODE (op1) == SSA_NAME)
 		  merge_pointed_to_info (ai, var, op1);
@@ -1892,8 +1894,10 @@ collect_points_to_info_r (tree var, tree stmt, void *data)
 	    /* Neither operand is a pointer?  VAR can be pointing
 	       anywhere.  FIXME: Is this right?  If we get here, we
 	       found PTR = INT_CST + INT_CST.  */
-	    if (!POINTER_TYPE_P (TREE_TYPE (op0))
-		&& !POINTER_TYPE_P (TREE_TYPE (op1)))
+	    if (!(POINTER_TYPE_P (TREE_TYPE (op0))
+		  && TREE_CODE (op0) != INTEGER_CST)
+		&& !(POINTER_TYPE_P (TREE_TYPE (op1))
+		     && TREE_CODE (op1) != INTEGER_CST))
 	      add_pointed_to_expr (var, rhs);
 	  }