re PR tree-optimization/84339 (Wrong-code with optimizing strlen)

	PR tree-optimization/84339
	* gimple-fold.c (get_range_strlen): Set *FLEXP to true when handling
	ARRAY_REF where first operand is array_at_struct_end_p COMPONENT_REF.
	Formatting fixes.

	* gcc.c-torture/execute/pr84339.c: New test.

From-SVN: r257618

gcc/ChangeLog

 2018-02-13  Jakub Jelinek  <jakub@redhat.com>
 
+	PR tree-optimization/84339
+	* gimple-fold.c (get_range_strlen): Set *FLEXP to true when handling
+	ARRAY_REF where first operand is array_at_struct_end_p COMPONENT_REF.
+	Formatting fixes.
+
 	PR middle-end/84309
 	* match.pd (pow(C,x) -> exp(log(C)*x)): Optimize instead into
 	exp2(log2(C)*x) if C is a power of 2 and c99 runtime is available.

gcc/gimple-fold.c

@@ -1380,9 +1380,15 @@ get_range_strlen (tree arg, tree length[2], bitmap *visited, int type,
 	      /* Set the minimum size to zero since the string in
 		 the array could have zero length.  */
 	      *minlen = ssize_int (0);
+
+	      if (TREE_CODE (TREE_OPERAND (arg, 0)) == COMPONENT_REF
+		  && type == TREE_TYPE (TREE_OPERAND (arg, 0))
+		  && array_at_struct_end_p (TREE_OPERAND (arg, 0)))
+		*flexp = true;
 	    }
 	  else if (TREE_CODE (arg) == COMPONENT_REF
-	      && TREE_CODE (TREE_TYPE (TREE_OPERAND (arg, 1))) == ARRAY_TYPE)
+		   && (TREE_CODE (TREE_TYPE (TREE_OPERAND (arg, 1)))
+		       == ARRAY_TYPE))
 	    {
 	      /* Use the type of the member array to determine the upper
 		 bound on the length of the array.  This may be overly
@@ -1428,7 +1434,7 @@ get_range_strlen (tree arg, tree length[2], bitmap *visited, int type,
 		      || integer_zerop (val))
 		    return false;
 		  val = wide_int_to_tree (TREE_TYPE (val),
-					  wi::sub(wi::to_wide (val), 1));
+					  wi::sub (wi::to_wide (val), 1));
 		  /* Set the minimum size to zero since the string in
 		     the array could have zero length.  */
 		  *minlen = ssize_int (0);

gcc/testsuite/ChangeLog

 2018-02-13  Jakub Jelinek  <jakub@redhat.com>
 
+	PR tree-optimization/84339
+	* gcc.c-torture/execute/pr84339.c: New test.
+
 	PR middle-end/84309
 	* gcc.dg/pr84309.c: New test.
 	* gcc.target/i386/pr84309.c: New test.

gcc/testsuite/gcc.c-torture/execute/pr84339.c

+/* PR tree-optimization/84339 */
+
+struct S { int a; char b[1]; };
+
+__attribute__((noipa)) int
+foo (struct S *p)
+{
+  return __builtin_strlen (&p->b[0]);
+}
+
+__attribute__((noipa)) int
+bar (struct S *p)
+{
+  return __builtin_strlen (p->b);
+}
+
+int
+main ()
+{
+  struct S *p = __builtin_malloc (sizeof (struct S) + 16);
+  if (p)
+    {
+      p->a = 1;
+      __builtin_strcpy (p->b, "abcdefg");
+      if (foo (p) != 7 || bar (p) != 7)
+	__builtin_abort ();
+      __builtin_free (p);
+    }
+  return 0;
+}