diff --git a/gcc/testsuite/gcc.dg/strlenopt-30.c b/gcc/testsuite/gcc.dg/strlenopt-30.c
new file mode 100644
index 0000000..603e23c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/strlenopt-30.c
@@ -0,0 +1,42 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-strlen" } */
+
+__attribute__((no_icf))
+_Bool f1(char *s)
+{
+  return __builtin_strstr (s, "hello") == s;
+}
+
+__attribute__((no_icf))
+_Bool f2(char *s)
+{
+  return s == __builtin_strstr (s, "hello");
+}
+
+__attribute__((no_icf))
+_Bool f3(char *s)
+{
+  return s != __builtin_strstr (s, "hello");
+}
+
+__attribute__((no_icf))
+_Bool f4(char *s, char *t)
+{
+  return __builtin_strstr (s, t) == s;
+}
+
+/* Do not perform transform in this case, since
+   t1 doesn't have single use.  */
+
+__attribute__((no_icf))
+_Bool f5(char *s, char *t)
+{
+  void foo(char *);
+
+  char *t1 = __builtin_strstr (s, t);
+  foo (t1);
+  return (t1 == s);
+}
+
+/* { dg-final { scan-tree-dump-times "__builtin_memcmp" 4 "strlen" } } */
+/* { dg-final { scan-tree-dump-times "__builtin_strlen" 1 "strlen" } } */
diff --git a/gcc/tree-ssa-strlen.c b/gcc/tree-ssa-strlen.c
index 339812e..b7f4cee 100644
--- a/gcc/tree-ssa-strlen.c
+++ b/gcc/tree-ssa-strlen.c
@@ -45,6 +45,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "ipa-chkp.h"
 #include "tree-hash-traits.h"
 #include "builtins.h"
+#include "tree-into-ssa.h"
 
 /* A vector indexed by SSA_NAME_VERSION.  0 means unknown, positive value
    is an index into strinfo vector, negative value stands for
@@ -2302,7 +2303,94 @@ strlen_optimize_stmt (gimple_stmt_iterator *gsi)
 	  else if (gimple_assign_rhs_code (stmt) == POINTER_PLUS_EXPR)
 	    handle_pointer_plus (gsi);
 	}
-      else if (TREE_CODE (lhs) != SSA_NAME && !TREE_SIDE_EFFECTS (lhs))
+
+      /* Fold strstr (s, t) == s to memcmp (s, t, strlen (t)) == 0.
+	 if var holding return value of strstr has single use.  */
+
+      else if (TREE_CODE (lhs) == SSA_NAME && INTEGRAL_TYPE_P (TREE_TYPE (lhs)))
+	{
+	  enum tree_code code = gimple_assign_rhs_code (stmt);
+	  if (code == EQ_EXPR || code == NE_EXPR)
+	    {
+	      tree rhs1 = gimple_assign_rhs1 (stmt);
+	      tree rhs2 = gimple_assign_rhs2 (stmt);
+	      if (TREE_CODE (rhs1) == SSA_NAME
+		  && TREE_CODE (rhs2) == SSA_NAME)
+		{
+		  gcall *call_stmt = dyn_cast<gcall *> (SSA_NAME_DEF_STMT (rhs1));
+		  if (!call_stmt)
+		    {
+		      call_stmt = dyn_cast<gcall *> (SSA_NAME_DEF_STMT (rhs2));
+		      tree tmp = rhs1;
+		      rhs1 = rhs2;
+		      rhs2 = tmp;
+		    }
+
+		  tree call_lhs;
+		  if (call_stmt
+		      && gimple_call_builtin_p (call_stmt, BUILT_IN_STRSTR)
+		      && (call_lhs = gimple_call_lhs (call_stmt))
+		      && has_single_use (call_lhs))
+		    {
+		      tree arg0 = gimple_call_arg (call_stmt, 0);
+		      if (operand_equal_p (arg0, rhs2, 0))
+			{
+			  tree arg1 = gimple_call_arg (call_stmt, 1);
+			  tree arg1_len = NULL_TREE;
+			  int idx = get_stridx (arg1);
+
+			  if (idx)
+			    {
+			      if (idx < 0)
+				arg1_len = build_int_cst (size_type_node,
+							  ~idx);
+			      else
+				{
+				  strinfo *si = get_strinfo (idx);
+				  if (si)
+				    arg1_len = get_string_length (si);
+				}
+			    }
+
+			  if (arg1_len == NULL_TREE)
+			    {
+			      gimple_stmt_iterator gsi;
+			      tree strlen_decl;
+			      gimple *strlen_call;
+
+			      strlen_decl = builtin_decl_explicit (BUILT_IN_STRLEN);
+			      strlen_call = gimple_build_call (strlen_decl, 1,
+							       arg1);
+			      arg1_len = make_ssa_name (size_type_node);
+			      gimple_call_set_lhs (strlen_call, arg1_len);
+			      update_stmt (strlen_call);
+			      gsi = gsi_for_stmt (call_stmt);
+			      gsi_insert_before (&gsi, strlen_call, GSI_SAME_STMT);
+			    }
+
+			  gimple_stmt_iterator gsi = gsi_for_stmt (call_stmt);
+			  tree memcmp_decl = builtin_decl_explicit (BUILT_IN_MEMCMP);
+			  gcall *memcmp_call
+			    = gimple_build_call (memcmp_decl, 3, arg0, arg1,
+						 arg1_len);
+			  tree memcmp_lhs = make_ssa_name (integer_type_node);
+			  gimple_call_set_lhs (memcmp_call, memcmp_lhs);
+			  update_stmt (memcmp_call);
+			  gsi_remove (&gsi, true);
+			  gsi_insert_before (&gsi, memcmp_call, GSI_SAME_STMT);
+
+			  gsi = gsi_for_stmt (stmt);
+			  tree zero = build_zero_cst (TREE_TYPE (memcmp_lhs));
+			  gassign *ga = gimple_build_assign (lhs, code,
+							     memcmp_lhs, zero);
+			  gsi_replace (&gsi, ga, false);
+			  update_ssa (TODO_update_ssa);
+			}
+		    }
+		}
+	    }
+	}
+    else if (TREE_CODE (lhs) != SSA_NAME && !TREE_SIDE_EFFECTS (lhs))
 	{
 	  tree type = TREE_TYPE (lhs);
 	  if (TREE_CODE (type) == ARRAY_TYPE)
