xtensa: fix PR target/82181

2017-09-11  Max Filippov  <jcmvbkbc@gmail.com>
gcc/
	* config/xtensa/xtensa.c (xtensa_mem_offset): Check that both
	words of E_DImode object are reachable by xtensa_uimm8x4 access.

From-SVN: r251986

gcc/ChangeLog

+2017-09-11  Max Filippov  <jcmvbkbc@gmail.com>
+
+	PR target/82181
+	* config/xtensa/xtensa.c (xtensa_mem_offset): Check that both
+	words of E_DImode object are reachable by xtensa_uimm8x4 access.
+
 2017-09-11  Vidya Praveen  <vidyapraveen@arm.com>
 
 	Revert r251800 and r251799.

gcc/config/xtensa/xtensa.c

@@ -615,6 +615,7 @@ xtensa_mem_offset (unsigned v, machine_mode mode)
     case E_HImode:
       return xtensa_uimm8x2 (v);
 
+    case E_DImode:
     case E_DFmode:
       return (xtensa_uimm8x4 (v) && xtensa_uimm8x4 (v + 4));