PR tree-optimization/91183 - strlen of a strcpy result with a conditional source not folded

PR tree-optimization/91183 - strlen of a strcpy result with a conditional source not folded
PR tree-optimization/86688 - missing -Wstringop-overflow using a non-string local array in strnlen with excessive bound

gcc/ChangeLog:

	PR tree-optimization/91183
	PR tree-optimization/86688
	* builtins.c (compute_objsize): Handle MEM_REF.
	* tree-ssa-strlen.c (class ssa_name_limit_t): New.
	(get_min_string_length): Remove.
	(count_nonzero_bytes): New function.
	(handle_char_store): Rename...
	(handle_store): to this.  Handle multibyte stores via integer types.
	(strlen_check_and_optimize_stmt): Adjust conditional and the called
	function name.

gcc/testsuite/ChangeLog:

	PR tree-optimization/91183
	PR tree-optimization/86688
	* gcc.dg/Wstringop-overflow-14.c: New test.
	* gcc.dg/attr-nonstring-2.c: Remove xfails.
	* gcc.dg/strlenopt-70.c: New test.
	* gcc.dg/strlenopt-71.c: New test.
	* gcc.dg/strlenopt-72.c: New test.
	* gcc.dg/strlenopt-8.c: Remove xfails.

From-SVN: r273783

1 files changed, 14 insertions, 0 deletions

diff --git a/gcc/builtins.c b/gcc/builtins.c
index e5a9261..695a9d1 100644
--- a/gcc/builtins.c
+++ b/gcc/builtins.c
@@ -3652,6 +3652,20 @@ compute_objsize (tree dest, int ostype)
   if (!ostype)
     return NULL_TREE;
 
+  if (TREE_CODE (dest) == MEM_REF)
+    {
+      tree ref = TREE_OPERAND (dest, 0);
+      tree off = TREE_OPERAND (dest, 1);
+      if (tree size = compute_objsize (ref, ostype))
+	{
+	  if (tree_int_cst_lt (off, size))
+	    return fold_build2 (MINUS_EXPR, size_type_node, size, off);
+	  return integer_zero_node;
+	}
+
+      return NULL_TREE;
+    }
+
   if (TREE_CODE (dest) != ADDR_EXPR)
     return NULL_TREE;