cmd/compile/internal/gc: give OASWB name

Change-Id: Iacb84421215ca80c7add2818118b2af1a650fd58
Reviewed-on: https://go-review.googlesource.com/11639Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/compile/internal/gc/opnames.go

@@ -33,6 +33,7 @@ var opnames = []string{
 	OAS2MAPR:         "AS2MAPR",
 	OAS2DOTTYPE:      "AS2DOTTYPE",
 	OASOP:            "ASOP",
+	OASWB:            "ASWB",
 	OCALL:            "CALL",
 	OCALLFUNC:        "CALLFUNC",
 	OCALLMETH:        "CALLMETH",