cmd/compile/internal/arm: merge cases in ssaGenValue

Merge case statement for OpARMSLL, OpARMSRL and OpARMSRA into an
existing one using the same logic.

Change-Id: Ic4224668228902e5188fb0559b5f1949cfea1381
Reviewed-on: https://go-review.googlesource.com/c/go/+/171724
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>

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

@@ -206,6 +206,9 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		ssa.OpARMADDD,
 		ssa.OpARMSUBF,
 		ssa.OpARMSUBD,
+		ssa.OpARMSLL,
+		ssa.OpARMSRL,
+		ssa.OpARMSRA,
 		ssa.OpARMMULF,
 		ssa.OpARMMULD,
 		ssa.OpARMNMULF,
@@ -247,18 +250,6 @@ func ssaGenValue(s *gc.SSAGenState, v *ssa.Value) {
 		p.Reg = r1
 		p.To.Type = obj.TYPE_REG
 		p.To.Reg = r
-	case ssa.OpARMSLL,
-		ssa.OpARMSRL,
-		ssa.OpARMSRA:
-		r := v.Reg()
-		r1 := v.Args[0].Reg()
-		r2 := v.Args[1].Reg()
-		p := s.Prog(v.Op.Asm())
-		p.From.Type = obj.TYPE_REG
-		p.From.Reg = r2
-		p.Reg = r1
-		p.To.Type = obj.TYPE_REG
-		p.To.Reg = r
 	case ssa.OpARMSRAcond:
 		// ARM shift instructions uses only the low-order byte of the shift amount
 		// generate conditional instructions to deal with large shifts