PR tree-optimization/86400 - set<string>::set<char (*)[2]) constructor does not work with array argument

gcc/ChangeLog:
	* tree-ssa-strlen.c (maybe_set_strlen_range): Use type size rather
	than its domain to compute its the upper bound of a char array.

gcc/testsuite/ChangeLog:
	* gcc.dg/strlenopt-47.c: New test.
	* gcc.dg/strlenopt-48.c: New test.

From-SVN: r262438

5 files changed, 94 insertions, 16 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 87cfd18..adaacc5 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2018-07-05  Martin Sebor  <msebor@redhat.com>
+
+	PR c++/86400
+	* tree-ssa-strlen.c (maybe_set_strlen_range): Use type size rather
+	than its domain to compute its the upper bound of a char array.
+
 2018-07-05  Nathan Sidwell  <nathan@acm.org>
 
 	Replace NO_IMPLICIT_EXTERN_C with SYSTEM_IMPLICIT_EXTERN_C.
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index c5acb69..9f2cc84 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2018-07-05  Martin Sebor  <msebor@redhat.com>
+
+	PR c++/86400
+	* gcc.dg/strlenopt-47.c: New test.
+	* gcc.dg/strlenopt-48.c: New test.
+
 2018-07-05  Tamar Christina  <tamar.christina@arm.com>
 
 	PR target/84711
diff --git a/gcc/testsuite/gcc.dg/strlenopt-47.c b/gcc/testsuite/gcc.dg/strlenopt-47.c
new file mode 100644
index 0000000..68945c7
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/strlenopt-47.c
@@ -0,0 +1,36 @@
+/* PR tree-optimization/86400 - set<string>::set<char (*)[2]) constructor
+   does not work with array argument
+   Verify that strlen() calls with two-character array elements of
+   multidimensional arrays whose higher order dimension is 1 are not
+   folded.
+   { dg-do compile }
+   { dg-options "-O2 -Wall -fdump-tree-optimized" } */
+
+#include "strlenopt.h"
+
+void f (void)
+{
+  extern char a[1][2];
+  int n = strlen (*a);
+  if (n != 1)
+    abort();
+}
+
+void g (void)
+{
+  extern char b[1][2];
+  int n = strlen (b[0]);
+  if (n != 1)
+    abort();
+}
+
+void h (void)
+{
+  extern char c[1][2];
+  int n = strlen (&c[0][0]);
+  if (n != 1)
+    abort();
+}
+
+/* { dg-final { scan-tree-dump-times "= strlen" 3 "optimized" } }
+   { dg-final { scan-tree-dump-times "abort" 3 "optimized" } } */
diff --git a/gcc/testsuite/gcc.dg/strlenopt-48.c b/gcc/testsuite/gcc.dg/strlenopt-48.c
new file mode 100644
index 0000000..39bb32d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/strlenopt-48.c
@@ -0,0 +1,35 @@
+/* PR tree-optimization/86400 - set<string>::set<char (*)[2]) constructor
+   does not work with array argument
+   Verify that strlen() calls with one-character array elements of
+   multidimensional arrays are still folded.
+   { dg-do compile }
+   { dg-options "-O2 -Wall -fdump-tree-optimized" } */
+
+#include "strlenopt.h"
+
+void f (void)
+{
+  extern char a[2][1];
+  int n = strlen (a[1]);
+  if (n)
+    abort();
+}
+
+void g (void)
+{
+  extern char b[3][2][1];
+  int n = strlen (b[2][1]);
+  if (n)
+    abort();
+}
+
+void h (void)
+{
+  extern char c[4][3][2][1];
+  int n = strlen (c[3][2][1]);
+  if (n)
+    abort();
+}
+
+/* { dg-final { scan-tree-dump-times "strlen" 0 "optimized" } }
+   { dg-final { scan-tree-dump-times "abort" 0 "optimized" } } */
diff --git a/gcc/tree-ssa-strlen.c b/gcc/tree-ssa-strlen.c
index 5807c79..736e2d9 100644
--- a/gcc/tree-ssa-strlen.c
+++ b/gcc/tree-ssa-strlen.c
@@ -1156,22 +1156,17 @@ maybe_set_strlen_range (tree lhs, tree src, tree bound)
       if (src_is_array && !array_at_struct_end_p (src))
 	{
 	  tree type = TREE_TYPE (src);
-	  if (tree dom = TYPE_DOMAIN (type))
-	    {
-	      tree maxval = TYPE_MAX_VALUE (dom);
-	      if (maxval)
-		max = wi::to_wide (maxval);
-	      else
-		max = wi::zero (min.get_precision ());
-
-	      /* For strlen() the upper bound above is equal to
-		 the longest string that can be stored in the array
-		 (i.e., it accounts for the terminating nul.  For
-		 strnlen() bump up the maximum by one since the array
-		 need not be nul-terminated.  */
-	      if (bound)
-		++max;
-	    }
+	  if (tree size = TYPE_SIZE_UNIT (type))
+	    if (size && TREE_CODE (size) == INTEGER_CST)
+	      max = wi::to_wide (size);
+
+	  /* For strlen() the upper bound above is equal to
+	     the longest string that can be stored in the array
+	     (i.e., it accounts for the terminating nul.  For
+	     strnlen() bump up the maximum by one since the array
+	     need not be nul-terminated.  */
+	  if (!bound && max != 0)
+	    --max;
 	}
       else
 	{