[ARC] Update legitimate constant hook.

Make sure we check the constants in all cases.

gcc/
2017-10-14  Claudiu Zissulescu  <claziss@synopsys.com>

	* config/arc/arc.c (arc_legitimate_constant_p): Always check all
	constants.

testsuite/
2017-10-14  Claudiu Zissulescu  <claziss@synopsys.com>

	* gcc.target/arc/tls-1.c: New test.

From-SVN: r255778

gcc/ChangeLog

+2017-12-18  Claudiu Zissulescu  <claziss@synopsys.com>
+
+	* config/arc/arc.c (arc_legitimate_constant_p): Always check all
+	constants.
+
 2017-12-18  Andreas Krebbel  <krebbel@linux.vnet.ibm.com>
 
 	PR target/83420

gcc/config/arc/arc.c

@@ -5999,12 +5999,6 @@ arc_return_addr_rtx (int count, ATTRIBUTE_UNUSED rtx frame)
 bool
 arc_legitimate_constant_p (machine_mode mode, rtx x)
 {
-  if (GET_CODE (x) == SYMBOL_REF && SYMBOL_REF_TLS_MODEL (x))
-    return false;
-
-  if (!flag_pic && mode != Pmode)
-    return true;
-
   switch (GET_CODE (x))
     {
     case CONST:

gcc/testsuite/ChangeLog

+2017-12-18  Claudiu Zissulescu  <claziss@synopsys.com>
+
+	* gcc.target/arc/tls-1.c: New test.
+
 2017-12-18  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/81877

gcc/testsuite/gcc.target/arc/tls-1.c

+/* { dg-do compile } */
+/* { dg-require-effective-target tls } */
+/* { dg-options "-O3 -std=gnu99" } */
+
+/* Check if addressing the `pos` member of struct is done via tls
+   mechanism.  */
+
+struct callchain_cursor {
+  int last;
+  long long pos;
+} __thread a;
+void fn1(struct callchain_cursor *p1)
+{
+  p1->pos++;
+}
+
+extern void fn3 (void);
+
+void fn2(void) {
+  struct callchain_cursor *b = &a;
+  while (1) {
+    fn3();
+    fn1(b);
+  }
+}
+/* { dg-final { scan-assembler "r25,@a@tpoff" } } */