internal/obj/arm64: remove CASE and BCASE

Fixes #10994

CASE and BCASE were used by 7c in switch statements, cmd/compile
does not use them, cmd/assemble couldn't assemble them, and the arm64
peephole optimiser didn't know about them.

Change-Id: Id04835fcb37e207f76d211ce54a4db9c057d6112
Reviewed-on: https://go-review.googlesource.com/14100Reviewed-by: Aram Hăvărneanu <aram@mgk.ro>
Run-TryBot: Aram Hăvărneanu <aram@mgk.ro>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/cmd/internal/obj/arm64/a.out.go

@@ -647,8 +647,6 @@ const (
 	AWORD
 	ADYNT
 	AINIT
-	ABCASE
-	ACASE
 	ADWORD
 	ASIGNAME
 	AGOK

src/cmd/internal/obj/arm64/anames.go

@@ -317,8 +317,6 @@ var Anames = []string{
 	"WORD",
 	"DYNT",
 	"INIT",
-	"BCASE",
-	"CASE",
 	"DWORD",
 	"SIGNAME",
 	"GOK",

src/cmd/internal/obj/arm64/asm7.go

@@ -468,8 +468,6 @@ var optab = []Optab{
 	{AFCCMPS, C_COND, C_REG, C_VCON, 57, 4, 0, 0, 0},
 	{AFCSELD, C_COND, C_REG, C_FREG, 18, 4, 0, 0, 0},
 	{AFCVTSD, C_FREG, C_NONE, C_FREG, 29, 4, 0, 0, 0},
-	{ACASE, C_REG, C_NONE, C_REG, 62, 4 * 4, 0, 0, 0},
-	{ABCASE, C_NONE, C_NONE, C_SBRA, 63, 4, 0, 0, 0},
 	{ACLREX, C_NONE, C_NONE, C_VCON, 38, 4, 0, 0, 0},
 	{ACLREX, C_NONE, C_NONE, C_NONE, 38, 4, 0, 0, 0},
 	{ACBZ, C_REG, C_NONE, C_SBRA, 39, 4, 0, 0, 0},
@@ -1570,8 +1568,6 @@ func buildop(ctxt *obj.Link) {
 			ADWORD,
 			obj.ARET,
 			obj.ATEXT,
-			ACASE,
-			ABCASE,
 			ASTP,
 			ALDP:
 			break
@@ -1801,7 +1797,6 @@ func SYSARG4(op1 int, Cn int, Cm int, op2 int) int {
 }
 
 func asmout(ctxt *obj.Link, p *obj.Prog, o *Optab, out []uint32) {
-	var lastcase *obj.Prog
 	o1 := uint32(0)
 	o2 := uint32(0)
 	o3 := uint32(0)
@@ -2699,28 +2694,6 @@ func asmout(ctxt *obj.Link, p *obj.Prog, o *Optab, out []uint32) {
 
 		o1 = ADR(0, uint32(d), uint32(p.To.Reg))
 
-	case 62: /* case Rv, Rt -> adr tab, Rt; movw Rt[R<<2], Rl; add Rt, Rl; br (Rl) */
-		// adr 4(pc), Rt
-		o1 = ADR(0, 4*4, uint32(p.To.Reg))
-		// movw Rt[Rv<<2], REGTMP
-		o2 = (2 << 30) | (7 << 27) | (2 << 22) | (1 << 21) | (3 << 13) | (1 << 12) | (2 << 10) | (uint32(p.From.Reg&31) << 16) | (uint32(p.To.Reg&31) << 5) | REGTMP&31
-		// add Rt, REGTMP
-		o3 = oprrr(ctxt, AADD) | (uint32(p.To.Reg) << 16) | (REGTMP << 5) | REGTMP
-		// br (REGTMP)
-		o4 = (0x6b << 25) | (0x1F << 16) | (REGTMP & 31 << 5)
-		lastcase = p
-
-	case 63: /* bcase */
-		if lastcase == nil {
-			ctxt.Diag("missing CASE\n%v", p)
-			break
-		}
-
-		if p.Pcond != nil {
-			o1 = uint32(p.Pcond.Pc - (lastcase.Pc + 4*4))
-			ctxt.Diag("FIXME: some relocation needed in bcase\n%v", p)
-		}
-
 		/* reloc ops */
 	case 64: /* movT R,addr -> adrp + add + movT R, (REGTMP) */
 		o1 = ADR(1, 0, REGTMP)

src/cmd/internal/obj/arm64/obj7.go

@@ -440,7 +440,7 @@ loop:
 	if p.Pcond != nil {
 		if a != ABL && p.Link != nil {
 			q = obj.Brchain(ctxt, p.Link)
-			if a != obj.ATEXT && a != ABCASE {
+			if a != obj.ATEXT {
 				if q != nil && (q.Mark&FOLL != 0) {
 					p.As = int16(relinv(a))
 					p.Link = p.Pcond
@@ -515,7 +515,6 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym) {
 			ACBZW,
 			ATBZ,
 			ATBNZ,
-			ABCASE,
 			AB,
 			ABEQ,
 			ABNE,