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

[Martin Liška]

Hi.

In order to fix the PR, I save temporary expression to a SSA_NAME that
is then used in the gcall.

Patch can bootstrap on ppc64le-redhat-linux and survives regression tests.

Ready to be installed?
Martin


gcc/ChangeLog:

2017-12-22  Martin Liska  <mli...@suse.cz>

        PR tree-optimization/83552
        * tree-ssa-strlen.c (fold_strstr_to_strncmp): Assign result
        of get_string_lenth to a SSA_NAME.

gcc/testsuite/ChangeLog:

2017-12-22  Martin Liska  <mli...@suse.cz>

        PR tree-optimization/83552
        * gcc.dg/pr83552.c: New test.
---
 gcc/testsuite/gcc.dg/pr83552.c | 13 +++++++++++++
 gcc/tree-ssa-strlen.c          |  7 ++++++-
 2 files changed, 19 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/gcc.dg/pr83552.c



diff --git a/gcc/testsuite/gcc.dg/pr83552.c b/gcc/testsuite/gcc.dg/pr83552.c
new file mode 100644
index 00000000000..993cdd26581
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr83552.c
@@ -0,0 +1,13 @@
+/* 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 ();
+}
diff --git a/gcc/tree-ssa-strlen.c b/gcc/tree-ssa-strlen.c
index e812bd1e735..43dc22d5ce0 100644
--- a/gcc/tree-ssa-strlen.c
+++ b/gcc/tree-ssa-strlen.c
@@ -3005,12 +3005,17 @@ 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);
+
+	      tree arg1_len_tmp = make_ssa_name (TREE_TYPE (arg1_len));
+	      gassign *arg1_stmt = gimple_build_assign (arg1_len_tmp, arg1_len);
 	      gcall *strncmp_call = gimple_build_call (strncmp_decl, 3,
-						      arg0, arg1, arg1_len);
+						      arg0, arg1,
+						      arg1_len_tmp);
 	      tree strncmp_lhs = make_ssa_name (integer_type_node);
 	      gimple_set_vuse (strncmp_call, gimple_vuse (call_stmt));
 	      gimple_call_set_lhs (strncmp_call, strncmp_lhs);
 	      gsi_remove (&gsi, true);
+	      gsi_insert_before (&gsi, arg1_stmt, GSI_SAME_STMT);
 	      gsi_insert_before (&gsi, strncmp_call, GSI_SAME_STMT);
 	      tree zero = build_zero_cst (TREE_TYPE (strncmp_lhs));