[dev.ssa] cmd/compile: make etypes readable

Change-Id: Id89ea3b458597dd93d269b9fe5475e9cccc6d992
Reviewed-on: https://go-review.googlesource.com/12562Reviewed-by: Keith Randall <khr@golang.org>

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

@@ -396,6 +396,7 @@ var etnames = []string{
 	TFORW:       "FORW",
 	TFIELD:      "FIELD",
 	TSTRING:     "STRING",
+	TUNSAFEPTR:  "TUNSAFEPTR",
 	TANY:        "ANY",
 }
 

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

@@ -790,7 +790,7 @@ func (s *state) ssaOp(op uint8, t *Type) ssa.Op {
 	}
 	x, ok := opToSSA[opAndType{op, etype}]
 	if !ok {
-		s.Unimplementedf("unhandled binary op %s etype=%d", opnames[op], etype)
+		s.Unimplementedf("unhandled binary op %s etype=%s", opnames[op], Econv(int(etype), 0))
 	}
 	return x
 }