[RS6000] TOC refs generated during reload

The generic reload fix for pr72771 exposed a problem with recognizing
-mcmodel=medium/large TOC references generated during reload.

	PR target/72771
	* config/rs6000/rs6000.c (toc_relative_expr_p): Allow (lo_sum (high))
	toc refs created during reload.  Update function comment.

From-SVN: r239240

gcc/ChangeLog

 2016-08-08  Alan Modra  <amodra@gmail.com>
 
+	PR target/72771
+	* config/rs6000/rs6000.c (toc_relative_expr_p): Allow (lo_sum (high))
+	toc refs created during reload.  Update function comment.
+
+2016-08-08  Alan Modra  <amodra@gmail.com>
+
 	PR target/72802
 	* config/rs6000/rs6000.md (mov<mode>_hardfloat): Sort
 	alternatives.  Put loads first, then stores, and reg/reg moves

gcc/config/rs6000/rs6000.c

@@ -7937,8 +7937,8 @@ constant_pool_expr_p (rtx op)
 static const_rtx tocrel_base, tocrel_offset;
 
 /* Return true if OP is a toc pointer relative address (the output
-   of create_TOC_reference).  If STRICT, do not match high part or
-   non-split -mcmodel=large/medium toc pointer relative addresses.  */
+   of create_TOC_reference).  If STRICT, do not match non-split
+   -mcmodel=large/medium toc pointer relative addresses.  */
 
 bool
 toc_relative_expr_p (const_rtx op, bool strict)
@@ -7948,13 +7948,17 @@ toc_relative_expr_p (const_rtx op, bool strict)
 
   if (TARGET_CMODEL != CMODEL_SMALL)
     {
-      /* Only match the low part.  */
-      if (GET_CODE (op) == LO_SUM
-	  && REG_P (XEXP (op, 0))
-	  && INT_REG_OK_FOR_BASE_P (XEXP (op, 0), strict))
-	op = XEXP (op, 1);
-      else if (strict)
+      /* When strict ensure we have everything tidy.  */
+      if (strict
+	  && !(GET_CODE (op) == LO_SUM
+	       && REG_P (XEXP (op, 0))
+	       && INT_REG_OK_FOR_BASE_P (XEXP (op, 0), strict)))
 	return false;
+
+      /* When not strict, allow non-split TOC addresses and also allow
+	 (lo_sum (high ..)) TOC addresses created during reload.  */
+      if (GET_CODE (op) == LO_SUM)
+	op = XEXP (op, 1);
     }
 
   tocrel_base = op;