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

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index cd4a1c5327b00401e181b0f24caf74f77ad7ec96..325eea600385e1f529f60a47a8ccd313b07a1ec9 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,5 +1,10 @@
 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.

diff --git a/gcc/gimple-fold.c b/gcc/gimple-fold.c
index 386169235553cb1bf915e517dc02ebdc7b042964..e556f050e43cbda185069d436c1127acc48e1b95 100644 (file)
--- a/gcc/gimple-fold.c
+++ b/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);

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index aafa6d3466f5a22ca6cab2cc551abb783c25a431..cbe0b84cb476918f94f6142d62096b4ea125aed0 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,8 @@
 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.

diff --git a/gcc/testsuite/gcc.c-torture/execute/pr84339.c b/gcc/testsuite/gcc.c-torture/execute/pr84339.c
new file mode 100644 (file)
index 0000000..06fa3a0
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/execute/pr84339.c
@@ -0,0 +1,30 @@
+/* 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;
+}