Assign result of get_string_lenth to a SSA_NAME (PR tree-optimization/83552).

2017-12-27  Martin Liska  <mliska@suse.cz>

	PR tree-optimization/83552
	* tree-ssa-strlen.c (fold_strstr_to_strncmp): Assign result
	of get_string_lenth to a SSA_NAME if not a GIMPLE value.
2017-12-27  Martin Liska  <mliska@suse.cz>

	PR tree-optimization/83552
	* gcc.dg/pr83552.c: New test.

From-SVN: r256009

gcc/ChangeLog

+2017-12-27  Martin Liska  <mliska@suse.cz>
+
+	PR tree-optimization/83552
+	* tree-ssa-strlen.c (fold_strstr_to_strncmp): Assign result
+	of get_string_lenth to a SSA_NAME if not a GIMPLE value.
+
 2017-12-27  Tom de Vries  <tom@codesourcery.com>
 
 	* config/nvptx/nvptx.c (nvptx_option_override): Disable

gcc/testsuite/ChangeLog

+2017-12-27  Martin Liska  <mliska@suse.cz>
+
+	PR tree-optimization/83552
+	* gcc.dg/pr83552.c: New test.
+
 2017-12-26  Thomas Koenig  <tkoenig@gcc.gnu.org>
 
 	PR fortran/83540

gcc/testsuite/gcc.dg/pr83552.c

+/* PR tree-optimization/83364 */
+/* { dg-options "-O2" } */
+
+char *b;
+char d[100];
+void a ();
+void
+c (void)
+{
+  __builtin_strcat (d, "12345");
+  if (__builtin_strstr (b, d) == b)
+    a ();
+}

gcc/tree-ssa-strlen.c

@@ -3005,6 +3005,16 @@ fold_strstr_to_strncmp (tree rhs1, tree rhs2, gimple *stmt)
 	    {
 	      gimple_stmt_iterator gsi = gsi_for_stmt (call_stmt);
 	      tree strncmp_decl = builtin_decl_explicit (BUILT_IN_STRNCMP);
+
+	      if (!is_gimple_val (arg1_len))
+		{
+		  tree arg1_len_tmp = make_ssa_name (TREE_TYPE (arg1_len));
+		  gassign *arg1_stmt = gimple_build_assign (arg1_len_tmp,
+							    arg1_len);
+		  gsi_insert_before (&gsi, arg1_stmt, GSI_SAME_STMT);
+		  arg1_len = arg1_len_tmp;
+		}
+
 	      gcall *strncmp_call = gimple_build_call (strncmp_decl, 3,
 						      arg0, arg1, arg1_len);
 	      tree strncmp_lhs = make_ssa_name (integer_type_node);