tcg: Add INDEX_op_extract2_{i32,i64}

This will let backends implement the double-word shift operation.

Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
diff --git a/tcg/tcg.c b/tcg/tcg.c
index 6a22c87..c0730f1 100644
--- a/tcg/tcg.c
+++ b/tcg/tcg.c
@@ -1426,6 +1426,8 @@
         return TCG_TARGET_HAS_extract_i32;
     case INDEX_op_sextract_i32:
         return TCG_TARGET_HAS_sextract_i32;
+    case INDEX_op_extract2_i32:
+        return TCG_TARGET_HAS_extract2_i32;
     case INDEX_op_add2_i32:
         return TCG_TARGET_HAS_add2_i32;
     case INDEX_op_sub2_i32:
@@ -1523,6 +1525,8 @@
         return TCG_TARGET_HAS_extract_i64;
     case INDEX_op_sextract_i64:
         return TCG_TARGET_HAS_sextract_i64;
+    case INDEX_op_extract2_i64:
+        return TCG_TARGET_HAS_extract2_i64;
     case INDEX_op_extrl_i64_i32:
         return TCG_TARGET_HAS_extrl_i64_i32;
     case INDEX_op_extrh_i64_i32: