var gactive uint32
func peep(firstp *obj.Prog) {
- // TODO(aram)
+ g := (*gc.Graph)(gc.Flowstart(firstp, nil))
+ if g == nil {
+ return
+ }
+ gactive = 0
+
+ var p *obj.Prog
+ var r *gc.Flow
+ var t int
+loop1:
+ if gc.Debug['P'] != 0 && gc.Debug['v'] != 0 {
+ gc.Dumpit("loop1", g.Start, 0)
+ }
+
+ t = 0
+ for r = g.Start; r != nil; r = r.Link {
+ p = r.Prog
+
+ // TODO(minux) Handle smaller moves. arm and amd64
+ // distinguish between moves that *must* sign/zero
+ // extend and moves that don't care so they
+ // can eliminate moves that don't care without
+ // breaking moves that do care. This might let us
+ // simplify or remove the next peep loop, too.
+ if p.As == arm64.AMOVD || p.As == arm64.AFMOVD {
+ if regtyp(&p.To) {
+ // Try to eliminate reg->reg moves
+ if regtyp(&p.From) {
+ if p.From.Type == p.To.Type {
+ if copyprop(r) {
+ excise(r)
+ t++
+ } else if subprop(r) && copyprop(r) {
+ excise(r)
+ t++
+ }
+ }
+ }
+ }
+ }
+ }
+
+ if t != 0 {
+ goto loop1
+ }
+
+ /*
+ * look for MOVB x,R; MOVB R,R (for small MOVs not handled above)
+ */
+ var p1 *obj.Prog
+ var r1 *gc.Flow
+ for r := (*gc.Flow)(g.Start); r != nil; r = r.Link {
+ p = r.Prog
+ switch p.As {
+ default:
+ continue
+
+ case arm64.AMOVH,
+ arm64.AMOVHU,
+ arm64.AMOVB,
+ arm64.AMOVBU,
+ arm64.AMOVW,
+ arm64.AMOVWU:
+ if p.To.Type != obj.TYPE_REG {
+ continue
+ }
+ }
+
+ r1 = r.Link
+ if r1 == nil {
+ continue
+ }
+ p1 = r1.Prog
+ if p1.As != p.As {
+ continue
+ }
+ if p1.From.Type != obj.TYPE_REG || p1.From.Reg != p.To.Reg {
+ continue
+ }
+ if p1.To.Type != obj.TYPE_REG || p1.To.Reg != p.To.Reg {
+ continue
+ }
+ excise(r1)
+ }
+
+ if gc.Debug['D'] > 1 {
+ goto ret /* allow following code improvement to be suppressed */
+ }
+
+ /* TODO(minux):
+ * look for OP x,y,R; CMP R, $0 -> OP.S x,y,R
+ * when OP can set condition codes correctly
+ */
+
+ret:
+ gc.Flowend(g)
}
func excise(r *gc.Flow) {
return a.Type == obj.TYPE_REG && arm64.REG_R0 <= a.Reg && a.Reg <= arm64.REG_F31 && a.Reg != arm64.REGZERO
}
+/*
+ * the idea is to substitute
+ * one register for another
+ * from one MOV to another
+ * MOV a, R1
+ * ADD b, R1 / no use of R2
+ * MOV R1, R2
+ * would be converted to
+ * MOV a, R2
+ * ADD b, R2
+ * MOV R2, R1
+ * hopefully, then the former or latter MOV
+ * will be eliminated by copy propagation.
+ *
+ * r0 (the argument, not the register) is the MOV at the end of the
+ * above sequences. This returns 1 if it modified any instructions.
+ */
+func subprop(r0 *gc.Flow) bool {
+ p := (*obj.Prog)(r0.Prog)
+ v1 := (*obj.Addr)(&p.From)
+ if !regtyp(v1) {
+ return false
+ }
+ v2 := (*obj.Addr)(&p.To)
+ if !regtyp(v2) {
+ return false
+ }
+ for r := gc.Uniqp(r0); r != nil; r = gc.Uniqp(r) {
+ if gc.Uniqs(r) == nil {
+ break
+ }
+ p = r.Prog
+ if p.As == obj.AVARDEF || p.As == obj.AVARKILL {
+ continue
+ }
+ if p.Info.Flags&gc.Call != 0 {
+ return false
+ }
+
+ if p.Info.Flags&(gc.RightRead|gc.RightWrite) == gc.RightWrite {
+ if p.To.Type == v1.Type {
+ if p.To.Reg == v1.Reg {
+ copysub(&p.To, v1, v2, 1)
+ if gc.Debug['P'] != 0 {
+ fmt.Printf("gotit: %v->%v\n%v", gc.Ctxt.Dconv(v1), gc.Ctxt.Dconv(v2), r.Prog)
+ if p.From.Type == v2.Type {
+ fmt.Printf(" excise")
+ }
+ fmt.Printf("\n")
+ }
+
+ for r = gc.Uniqs(r); r != r0; r = gc.Uniqs(r) {
+ p = r.Prog
+ copysub(&p.From, v1, v2, 1)
+ copysub1(p, v1, v2, 1)
+ copysub(&p.To, v1, v2, 1)
+ if gc.Debug['P'] != 0 {
+ fmt.Printf("%v\n", r.Prog)
+ }
+ }
+
+ t := int(int(v1.Reg))
+ v1.Reg = v2.Reg
+ v2.Reg = int16(t)
+ if gc.Debug['P'] != 0 {
+ fmt.Printf("%v last\n", r.Prog)
+ }
+ return true
+ }
+ }
+ }
+
+ if copyau(&p.From, v2) || copyau1(p, v2) || copyau(&p.To, v2) {
+ break
+ }
+ if copysub(&p.From, v1, v2, 0) != 0 || copysub1(p, v1, v2, 0) != 0 || copysub(&p.To, v1, v2, 0) != 0 {
+ break
+ }
+ }
+
+ return false
+}
+
+/*
+ * The idea is to remove redundant copies.
+ * v1->v2 F=0
+ * (use v2 s/v2/v1/)*
+ * set v1 F=1
+ * use v2 return fail (v1->v2 move must remain)
+ * -----------------
+ * v1->v2 F=0
+ * (use v2 s/v2/v1/)*
+ * set v1 F=1
+ * set v2 return success (caller can remove v1->v2 move)
+ */
+func copyprop(r0 *gc.Flow) bool {
+ p := (*obj.Prog)(r0.Prog)
+ v1 := (*obj.Addr)(&p.From)
+ v2 := (*obj.Addr)(&p.To)
+ if copyas(v1, v2) {
+ if gc.Debug['P'] != 0 {
+ fmt.Printf("eliminating self-move\n", r0.Prog)
+ }
+ return true
+ }
+
+ gactive++
+ if gc.Debug['P'] != 0 {
+ fmt.Printf("trying to eliminate %v->%v move from:\n%v\n", gc.Ctxt.Dconv(v1), gc.Ctxt.Dconv(v2), r0.Prog)
+ }
+ return copy1(v1, v2, r0.S1, 0)
+}
+
+// copy1 replaces uses of v2 with v1 starting at r and returns 1 if
+// all uses were rewritten.
+func copy1(v1 *obj.Addr, v2 *obj.Addr, r *gc.Flow, f int) bool {
+ if uint32(r.Active) == gactive {
+ if gc.Debug['P'] != 0 {
+ fmt.Printf("act set; return 1\n")
+ }
+ return true
+ }
+
+ r.Active = int32(gactive)
+ if gc.Debug['P'] != 0 {
+ fmt.Printf("copy1 replace %v with %v f=%d\n", gc.Ctxt.Dconv(v2), gc.Ctxt.Dconv(v1), f)
+ }
+ var t int
+ var p *obj.Prog
+ for ; r != nil; r = r.S1 {
+ p = r.Prog
+ if gc.Debug['P'] != 0 {
+ fmt.Printf("%v", p)
+ }
+ if f == 0 && gc.Uniqp(r) == nil {
+ // Multiple predecessors; conservatively
+ // assume v1 was set on other path
+ f = 1
+
+ if gc.Debug['P'] != 0 {
+ fmt.Printf("; merge; f=%d", f)
+ }
+ }
+
+ t = copyu(p, v2, nil)
+ switch t {
+ case 2: /* rar, can't split */
+ if gc.Debug['P'] != 0 {
+ fmt.Printf("; %v rar; return 0\n", gc.Ctxt.Dconv(v2))
+ }
+ return false
+
+ case 3: /* set */
+ if gc.Debug['P'] != 0 {
+ fmt.Printf("; %v set; return 1\n", gc.Ctxt.Dconv(v2))
+ }
+ return true
+
+ case 1, /* used, substitute */
+ 4: /* use and set */
+ if f != 0 {
+ if gc.Debug['P'] == 0 {
+ return false
+ }
+ if t == 4 {
+ fmt.Printf("; %v used+set and f=%d; return 0\n", gc.Ctxt.Dconv(v2), f)
+ } else {
+ fmt.Printf("; %v used and f=%d; return 0\n", gc.Ctxt.Dconv(v2), f)
+ }
+ return false
+ }
+
+ if copyu(p, v2, v1) != 0 {
+ if gc.Debug['P'] != 0 {
+ fmt.Printf("; sub fail; return 0\n")
+ }
+ return false
+ }
+
+ if gc.Debug['P'] != 0 {
+ fmt.Printf("; sub %v->%v\n => %v", gc.Ctxt.Dconv(v2), gc.Ctxt.Dconv(v1), p)
+ }
+ if t == 4 {
+ if gc.Debug['P'] != 0 {
+ fmt.Printf("; %v used+set; return 1\n", gc.Ctxt.Dconv(v2))
+ }
+ return true
+ }
+ }
+
+ if f == 0 {
+ t = copyu(p, v1, nil)
+ if f == 0 && (t == 2 || t == 3 || t == 4) {
+ f = 1
+ if gc.Debug['P'] != 0 {
+ fmt.Printf("; %v set and !f; f=%d", gc.Ctxt.Dconv(v1), f)
+ }
+ }
+ }
+
+ if gc.Debug['P'] != 0 {
+ fmt.Printf("\n")
+ }
+ if r.S2 != nil {
+ if !copy1(v1, v2, r.S2, f) {
+ return false
+ }
+ }
+ }
+
+ return true
+}
+
+// If s==nil, copyu returns the set/use of v in p; otherwise, it
+// modifies p to replace reads of v with reads of s and returns 0 for
+// success or non-zero for failure.
+//
+// If s==nil, copy returns one of the following values:
+// 1 if v only used
+// 2 if v is set and used in one address (read-alter-rewrite;
+// can't substitute)
+// 3 if v is only set
+// 4 if v is set in one address and used in another (so addresses
+// can be rewritten independently)
+// 0 otherwise (not touched)
+func copyu(p *obj.Prog, v *obj.Addr, s *obj.Addr) int {
+ if p.From3.Type != obj.TYPE_NONE {
+ // 7g never generates a from3
+ fmt.Printf("copyu: from3 (%v) not implemented\n", gc.Ctxt.Dconv(&p.From3))
+ }
+ if p.To2.Type != obj.TYPE_NONE {
+ // 7g never generates a to2
+ fmt.Printf("copyu: to2 (%v) not implemented\n", gc.Ctxt.Dconv(&p.To2))
+ }
+
+ switch p.As {
+ default:
+ fmt.Printf("copyu: can't find %v\n", obj.Aconv(int(p.As)))
+ return 2
+
+ case obj.ANOP, /* read p->from, write p->to */
+ arm64.ANEG,
+ arm64.AFNEGD,
+ arm64.AFNEGS,
+ arm64.AFSQRTD,
+ arm64.AFCVTZSD,
+ arm64.AFCVTZSS,
+ arm64.AFCVTZSDW,
+ arm64.AFCVTZSSW,
+ arm64.AFCVTZUD,
+ arm64.AFCVTZUS,
+ arm64.AFCVTZUDW,
+ arm64.AFCVTZUSW,
+ arm64.AFCVTSD,
+ arm64.AFCVTDS,
+ arm64.ASCVTFD,
+ arm64.ASCVTFS,
+ arm64.ASCVTFWD,
+ arm64.ASCVTFWS,
+ arm64.AUCVTFD,
+ arm64.AUCVTFS,
+ arm64.AUCVTFWD,
+ arm64.AUCVTFWS,
+ arm64.AMOVB,
+ arm64.AMOVBU,
+ arm64.AMOVH,
+ arm64.AMOVHU,
+ arm64.AMOVW,
+ arm64.AMOVWU,
+ arm64.AMOVD,
+ arm64.AFMOVS,
+ arm64.AFMOVD:
+ if p.Scond == 0 {
+ if s != nil {
+ if copysub(&p.From, v, s, 1) != 0 {
+ return 1
+ }
+
+ // Update only indirect uses of v in p->to
+ if !copyas(&p.To, v) {
+ if copysub(&p.To, v, s, 1) != 0 {
+ return 1
+ }
+ }
+ return 0
+ }
+
+ if copyas(&p.To, v) {
+ // Fix up implicit from
+ if p.From.Type == obj.TYPE_NONE {
+ p.From = p.To
+ }
+ if copyau(&p.From, v) {
+ return 4
+ }
+ return 3
+ }
+
+ if copyau(&p.From, v) {
+ return 1
+ }
+ if copyau(&p.To, v) {
+ // p->to only indirectly uses v
+ return 1
+ }
+
+ return 0
+ }
+
+ /* rar p->from, write p->to or read p->from, rar p->to */
+ if p.From.Type == obj.TYPE_MEM {
+ if copyas(&p.From, v) {
+ // No s!=nil check; need to fail
+ // anyway in that case
+ return 2
+ }
+
+ if s != nil {
+ if copysub(&p.To, v, s, 1) != 0 {
+ return 1
+ }
+ return 0
+ }
+
+ if copyas(&p.To, v) {
+ return 3
+ }
+ } else if p.To.Type == obj.TYPE_MEM {
+ if copyas(&p.To, v) {
+ return 2
+ }
+ if s != nil {
+ if copysub(&p.From, v, s, 1) != 0 {
+ return 1
+ }
+ return 0
+ }
+
+ if copyau(&p.From, v) {
+ return 1
+ }
+ } else {
+ fmt.Printf("copyu: bad %v\n", p)
+ }
+
+ return 0
+
+ case arm64.AADD, /* read p->from, read p->reg, write p->to */
+ arm64.ASUB,
+ arm64.AAND,
+ arm64.AORR,
+ arm64.AEOR,
+ arm64.AMUL,
+ arm64.ASMULL,
+ arm64.AUMULL,
+ arm64.ASMULH,
+ arm64.AUMULH,
+ arm64.ASDIV,
+ arm64.AUDIV,
+ arm64.ALSL,
+ arm64.ALSR,
+ arm64.AASR,
+ arm64.AFADDD,
+ arm64.AFADDS,
+ arm64.AFSUBD,
+ arm64.AFSUBS,
+ arm64.AFMULD,
+ arm64.AFMULS,
+ arm64.AFDIVD,
+ arm64.AFDIVS:
+ if s != nil {
+ if copysub(&p.From, v, s, 1) != 0 {
+ return 1
+ }
+ if copysub1(p, v, s, 1) != 0 {
+ return 1
+ }
+
+ // Update only indirect uses of v in p->to
+ if !copyas(&p.To, v) {
+ if copysub(&p.To, v, s, 1) != 0 {
+ return 1
+ }
+ }
+ return 0
+ }
+
+ if copyas(&p.To, v) {
+ if p.Reg == 0 {
+ // Fix up implicit reg (e.g., ADD
+ // R3,R4 -> ADD R3,R4,R4) so we can
+ // update reg and to separately.
+ p.Reg = p.To.Reg
+ }
+
+ if copyau(&p.From, v) {
+ return 4
+ }
+ if copyau1(p, v) {
+ return 4
+ }
+ return 3
+ }
+
+ if copyau(&p.From, v) {
+ return 1
+ }
+ if copyau1(p, v) {
+ return 1
+ }
+ if copyau(&p.To, v) {
+ return 1
+ }
+ return 0
+
+ case arm64.ABEQ,
+ arm64.ABNE,
+ arm64.ABGE,
+ arm64.ABLT,
+ arm64.ABGT,
+ arm64.ABLE,
+ arm64.ABLO,
+ arm64.ABLS,
+ arm64.ABHI,
+ arm64.ABHS:
+ return 0
+
+ case obj.ACHECKNIL, /* read p->from */
+ arm64.ACMP, /* read p->from, read p->reg */
+ arm64.AFCMPD,
+ arm64.AFCMPS:
+ if s != nil {
+ if copysub(&p.From, v, s, 1) != 0 {
+ return 1
+ }
+ return copysub1(p, v, s, 1)
+ }
+
+ if copyau(&p.From, v) {
+ return 1
+ }
+ if copyau1(p, v) {
+ return 1
+ }
+ return 0
+
+ case arm64.AB: /* read p->to */
+ if s != nil {
+ if copysub(&p.To, v, s, 1) != 0 {
+ return 1
+ }
+ return 0
+ }
+
+ if copyau(&p.To, v) {
+ return 1
+ }
+ return 0
+
+ case obj.ARET: /* funny */
+ if s != nil {
+ return 0
+ }
+
+ // All registers die at this point, so claim
+ // everything is set (and not used).
+ return 3
+
+ case arm64.ABL: /* funny */
+ if p.From.Type == obj.TYPE_REG && v.Type == obj.TYPE_REG && p.From.Reg == v.Reg {
+ return 2
+ }
+
+ if s != nil {
+ if copysub(&p.To, v, s, 1) != 0 {
+ return 1
+ }
+ return 0
+ }
+
+ if copyau(&p.To, v) {
+ return 4
+ }
+ return 3
+
+ // R31 is zero, used by DUFFZERO, cannot be substituted.
+ // R16 is ptr to memory, used and set, cannot be substituted.
+ case obj.ADUFFZERO:
+ if v.Type == obj.TYPE_REG {
+ if v.Reg == 31 {
+ return 1
+ }
+ if v.Reg == 16 {
+ return 2
+ }
+ }
+
+ return 0
+
+ // R16, R17 are ptr to src, dst, used and set, cannot be substituted.
+ // R27 is scratch, set by DUFFCOPY, cannot be substituted.
+ case obj.ADUFFCOPY:
+ if v.Type == obj.TYPE_REG {
+ if v.Reg == 16 || v.Reg == 17 {
+ return 2
+ }
+ if v.Reg == 27 {
+ return 3
+ }
+ }
+
+ return 0
+
+ case arm64.AHINT,
+ obj.ATEXT,
+ obj.APCDATA,
+ obj.AFUNCDATA,
+ obj.AVARDEF,
+ obj.AVARKILL:
+ return 0
+ }
+}
+
+// copyas returns 1 if a and v address the same register.
+//
+// If a is the from operand, this means this operation reads the
+// register in v. If a is the to operand, this means this operation
+// writes the register in v.
+func copyas(a *obj.Addr, v *obj.Addr) bool {
+ if regtyp(v) {
+ if a.Type == v.Type {
+ if a.Reg == v.Reg {
+ return true
+ }
+ }
+ }
+ return false
+}
+
+// copyau returns 1 if a either directly or indirectly addresses the
+// same register as v.
+//
+// If a is the from operand, this means this operation reads the
+// register in v. If a is the to operand, this means the operation
+// either reads or writes the register in v (if !copyas(a, v), then
+// the operation reads the register in v).
+func copyau(a *obj.Addr, v *obj.Addr) bool {
+ if copyas(a, v) {
+ return true
+ }
+ if v.Type == obj.TYPE_REG {
+ if a.Type == obj.TYPE_MEM || (a.Type == obj.TYPE_ADDR && a.Reg != 0) {
+ if v.Reg == a.Reg {
+ return true
+ }
+ }
+ }
+ return false
+}
+
+// copyau1 returns 1 if p->reg references the same register as v and v
+// is a direct reference.
+func copyau1(p *obj.Prog, v *obj.Addr) bool {
+ if regtyp(v) && v.Reg != 0 {
+ if p.Reg == v.Reg {
+ return true
+ }
+ }
+ return false
+}
+
+// copysub replaces v with s in a if f!=0 or indicates it if could if f==0.
+// Returns 1 on failure to substitute (it always succeeds on arm64).
+func copysub(a *obj.Addr, v *obj.Addr, s *obj.Addr, f int) int {
+ if f != 0 {
+ if copyau(a, v) {
+ a.Reg = s.Reg
+ }
+ }
+ return 0
+}
+
+// copysub1 replaces v with s in p1->reg if f!=0 or indicates if it could if f==0.
+// Returns 1 on failure to substitute (it always succeeds on arm64).
+func copysub1(p1 *obj.Prog, v *obj.Addr, s *obj.Addr, f int) int {
+ if f != 0 {
+ if copyau1(p1, v) {
+ p1.Reg = s.Reg
+ }
+ }
+ return 0
+}
+
func sameaddr(a *obj.Addr, v *obj.Addr) bool {
if a.Type != v.Type {
return false