[ARC] Fix legitimize pic address.

There are cases when an pic address gets complicated, and it needs to
be resolved via force_reg function found in
prepare_move_operands. When this happens, we need to disambiguate the
pic address and re-legitimize it.

gcc/
xxxx-xx-xx  Claudiu Zissulescu  <claziss@synopsys.com>

	* config/arc/arc.c (arc_legitimize_pic_address): Consider UNSPECs
	as well, if interesting recover the symbol and re-legitimize the
	pic address.

gcc/testsuite/
xxxx-xx-xx  Claudiu Zissulescu  <claziss@synopsys.com>

	* gcc.target/arc/pic-2.c: New file.

From-SVN: r278056

gcc/ChangeLog

+2019-11-11  Claudiu Zissulescu <claziss@gmail.com>
+
+	* config/arc/arc.c (arc_legitimize_pic_address): Consider UNSPECs
+	as well, if interesting recover the symbol and re-legitimize the
+	pic address.
+
 2019-11-11  Martin Liska  <mliska@suse.cz>
 
 	* dbgcnt.def (DEBUG_COUNTER): Sort counters

gcc/config/arc/arc.c

@@ -6219,6 +6219,22 @@ arc_legitimize_pic_address (rtx addr)
 
   switch (GET_CODE (addr))
     {
+    case UNSPEC:
+      /* Can be one or our GOT or GOTOFFPC unspecs.  This situation
+	 happens when an address is not a legitimate constant and we
+	 need the resolve it via force_reg in
+	 prepare_move_operands.  */
+      switch (XINT (addr, 1))
+	{
+	case ARC_UNSPEC_GOT:
+	case ARC_UNSPEC_GOTOFFPC:
+	  /* Recover the symbol ref.  */
+	  addr = XVECEXP (addr, 0, 0);
+	  break;
+	default:
+	  return addr;
+	}
+      /* Fall through.  */
     case SYMBOL_REF:
       /* TLS symbols are handled in different place.  */
       if (SYMBOL_REF_TLS_MODEL (addr))

gcc/testsuite/ChangeLog

+2019-11-11  Claudiu Zissulescu <claziss@gmail.com>
+
+	* gcc.target/arc/pic-2.c: New file.
+
 2019-11-11  Tobias Burnus  <tobias@codesourcery.com>
 	    Mark Eggleston  <mark.eggleston@codethink.com>
 

gcc/testsuite/gcc.target/arc/pic-2.c

+/* { dg-do compile } */
+/* { dg-skip-if "PIC not available for ARC6xx" { arc6xx } } */
+/* { dg-options "-mno-sdata -O2 -fpic -fno-builtin" } */
+
+/* Check if we resolve correctly complex PIC addresses.  */
+
+char *foo (unsigned size)
+{
+  static char buf[32];
+  register int i;
+
+  if (size > 31)
+    size = 31;
+
+  for (i = 0; i < size; i++)
+    {
+      buf[i] = ' ';
+    }
+  buf[size] = '\0';
+  return buf;
+}
+
+/* { dg-final { scan-assembler "@buf.\[0-9\]\+@pcl-1" } } */