diff options
Diffstat (limited to 'src/cmd/6g/peep.go')
| -rw-r--r-- | src/cmd/6g/peep.go | 1077 |
1 files changed, 1077 insertions, 0 deletions
diff --git a/src/cmd/6g/peep.go b/src/cmd/6g/peep.go new file mode 100644 index 0000000000..9870ca5e4e --- /dev/null +++ b/src/cmd/6g/peep.go @@ -0,0 +1,1077 @@ +// Derived from Inferno utils/6c/peep.c +// http://code.google.com/p/inferno-os/source/browse/utils/6c/peep.c +// +// Copyright © 1994-1999 Lucent Technologies Inc. All rights reserved. +// Portions Copyright © 1995-1997 C H Forsyth (forsyth@terzarima.net) +// Portions Copyright © 1997-1999 Vita Nuova Limited +// Portions Copyright © 2000-2007 Vita Nuova Holdings Limited (www.vitanuova.com) +// Portions Copyright © 2004,2006 Bruce Ellis +// Portions Copyright © 2005-2007 C H Forsyth (forsyth@terzarima.net) +// Revisions Copyright © 2000-2007 Lucent Technologies Inc. and others +// Portions Copyright © 2009 The Go Authors. All rights reserved. +// +// Permission is hereby granted, free of charge, to any person obtaining a copy +// of this software and associated documentation files (the "Software"), to deal +// in the Software without restriction, including without limitation the rights +// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell +// copies of the Software, and to permit persons to whom the Software is +// furnished to do so, subject to the following conditions: +// +// The above copyright notice and this permission notice shall be included in +// all copies or substantial portions of the Software. +// +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR +// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, +// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE +// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER +// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, +// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN +// THE SOFTWARE. + +package main + +import ( + "cmd/internal/obj" + "cmd/internal/obj/x86" + "fmt" +) +import "cmd/internal/gc" + +var gactive uint32 + +const ( + exregoffset = x86.REG_R15 +) + +// do we need the carry bit +func needc(p *obj.Prog) bool { + var info gc.ProgInfo + + for p != nil { + proginfo(&info, p) + if info.Flags&gc.UseCarry != 0 { + return true + } + if info.Flags&(gc.SetCarry|gc.KillCarry) != 0 { + return false + } + p = p.Link + } + + return false +} + +func rnops(r *gc.Flow) *gc.Flow { + var p *obj.Prog + var r1 *gc.Flow + + if r != nil { + for { + p = r.Prog + if p.As != obj.ANOP || p.From.Type != obj.TYPE_NONE || p.To.Type != obj.TYPE_NONE { + break + } + r1 = gc.Uniqs(r) + if r1 == nil { + break + } + r = r1 + } + } + + return r +} + +func peep(firstp *obj.Prog) { + var r *gc.Flow + var r1 *gc.Flow + var g *gc.Graph + var p *obj.Prog + var p1 *obj.Prog + var t int + + g = gc.Flowstart(firstp, nil) + if g == nil { + return + } + gactive = 0 + + // byte, word arithmetic elimination. + elimshortmov(g) + + // constant propagation + // find MOV $con,R followed by + // another MOV $con,R without + // setting R in the interim + for r = g.Start; r != nil; r = r.Link { + p = r.Prog + switch p.As { + case x86.ALEAL, + x86.ALEAQ: + if regtyp(&p.To) { + if p.From.Sym != nil { + if p.From.Index == x86.REG_NONE { + conprop(r) + } + } + } + + case x86.AMOVB, + x86.AMOVW, + x86.AMOVL, + x86.AMOVQ, + x86.AMOVSS, + x86.AMOVSD: + if regtyp(&p.To) { + if p.From.Type == obj.TYPE_CONST || p.From.Type == obj.TYPE_FCONST { + conprop(r) + } + } + } + } + +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 + switch p.As { + case x86.AMOVL, + x86.AMOVQ, + x86.AMOVSS, + x86.AMOVSD: + if regtyp(&p.To) { + if regtyp(&p.From) { + if copyprop(g, r) { + excise(r) + t++ + } else if subprop(r) && copyprop(g, r) { + excise(r) + t++ + } + } + } + + case x86.AMOVBLZX, + x86.AMOVWLZX, + x86.AMOVBLSX, + x86.AMOVWLSX: + if regtyp(&p.To) { + r1 = rnops(gc.Uniqs(r)) + if r1 != nil { + p1 = r1.Prog + if p.As == p1.As && p.To.Type == p1.From.Type && p.To.Reg == p1.From.Reg { + p1.As = x86.AMOVL + t++ + } + } + } + + case x86.AMOVBQSX, + x86.AMOVBQZX, + x86.AMOVWQSX, + x86.AMOVWQZX, + x86.AMOVLQSX, + x86.AMOVLQZX, + x86.AMOVQL: + if regtyp(&p.To) { + r1 = rnops(gc.Uniqs(r)) + if r1 != nil { + p1 = r1.Prog + if p.As == p1.As && p.To.Type == p1.From.Type && p.To.Reg == p1.From.Reg { + p1.As = x86.AMOVQ + t++ + } + } + } + + case x86.AADDL, + x86.AADDQ, + x86.AADDW: + if p.From.Type != obj.TYPE_CONST || needc(p.Link) { + break + } + if p.From.Offset == -1 { + if p.As == x86.AADDQ { + p.As = x86.ADECQ + } else if p.As == x86.AADDL { + p.As = x86.ADECL + } else { + p.As = x86.ADECW + } + p.From = obj.Addr{} + break + } + + if p.From.Offset == 1 { + if p.As == x86.AADDQ { + p.As = x86.AINCQ + } else if p.As == x86.AADDL { + p.As = x86.AINCL + } else { + p.As = x86.AINCW + } + p.From = obj.Addr{} + break + } + + case x86.ASUBL, + x86.ASUBQ, + x86.ASUBW: + if p.From.Type != obj.TYPE_CONST || needc(p.Link) { + break + } + if p.From.Offset == -1 { + if p.As == x86.ASUBQ { + p.As = x86.AINCQ + } else if p.As == x86.ASUBL { + p.As = x86.AINCL + } else { + p.As = x86.AINCW + } + p.From = obj.Addr{} + break + } + + if p.From.Offset == 1 { + if p.As == x86.ASUBQ { + p.As = x86.ADECQ + } else if p.As == x86.ASUBL { + p.As = x86.ADECL + } else { + p.As = x86.ADECW + } + p.From = obj.Addr{} + break + } + } + } + + if t != 0 { + goto loop1 + } + + // MOVLQZX removal. + // The MOVLQZX exists to avoid being confused for a + // MOVL that is just copying 32-bit data around during + // copyprop. Now that copyprop is done, remov MOVLQZX R1, R2 + // if it is dominated by an earlier ADDL/MOVL/etc into R1 that + // will have already cleared the high bits. + // + // MOVSD removal. + // We never use packed registers, so a MOVSD between registers + // can be replaced by MOVAPD, which moves the pair of float64s + // instead of just the lower one. We only use the lower one, but + // the processor can do better if we do moves using both. + for r = g.Start; r != nil; r = r.Link { + p = r.Prog + if p.As == x86.AMOVLQZX { + if regtyp(&p.From) { + if p.From.Type == p.To.Type && p.From.Reg == p.To.Reg { + if prevl(r, int(p.From.Reg)) { + excise(r) + } + } + } + } + + if p.As == x86.AMOVSD { + if regtyp(&p.From) { + if regtyp(&p.To) { + p.As = x86.AMOVAPD + } + } + } + } + + // load pipelining + // push any load from memory as early as possible + // to give it time to complete before use. + for r = g.Start; r != nil; r = r.Link { + p = r.Prog + switch p.As { + case x86.AMOVB, + x86.AMOVW, + x86.AMOVL, + x86.AMOVQ, + x86.AMOVLQZX: + if regtyp(&p.To) && !regconsttyp(&p.From) { + pushback(r) + } + } + } + + gc.Flowend(g) +} + +func pushback(r0 *gc.Flow) { + var r *gc.Flow + var b *gc.Flow + var p0 *obj.Prog + var p *obj.Prog + var t obj.Prog + + b = nil + p0 = r0.Prog + for r = gc.Uniqp(r0); r != nil && gc.Uniqs(r) != nil; r = gc.Uniqp(r) { + p = r.Prog + if p.As != obj.ANOP { + if !regconsttyp(&p.From) || !regtyp(&p.To) { + break + } + if copyu(p, &p0.To, nil) != 0 || copyu(p0, &p.To, nil) != 0 { + break + } + } + + if p.As == obj.ACALL { + break + } + b = r + } + + if b == nil { + if gc.Debug['v'] != 0 { + fmt.Printf("no pushback: %v\n", r0.Prog) + if r != nil { + fmt.Printf("\t%v [%d]\n", r.Prog, gc.Uniqs(r) != nil) + } + } + + return + } + + if gc.Debug['v'] != 0 { + fmt.Printf("pushback\n") + for r = b; ; r = r.Link { + fmt.Printf("\t%v\n", r.Prog) + if r == r0 { + break + } + } + } + + t = *r0.Prog + for r = gc.Uniqp(r0); ; r = gc.Uniqp(r) { + p0 = r.Link.Prog + p = r.Prog + p0.As = p.As + p0.Lineno = p.Lineno + p0.From = p.From + p0.To = p.To + + if r == b { + break + } + } + + p0 = r.Prog + p0.As = t.As + p0.Lineno = t.Lineno + p0.From = t.From + p0.To = t.To + + if gc.Debug['v'] != 0 { + fmt.Printf("\tafter\n") + for r = b; ; r = r.Link { + fmt.Printf("\t%v\n", r.Prog) + if r == r0 { + break + } + } + } +} + +func excise(r *gc.Flow) { + var p *obj.Prog + + p = r.Prog + if gc.Debug['P'] != 0 && gc.Debug['v'] != 0 { + fmt.Printf("%v ===delete===\n", p) + } + + obj.Nopout(p) + + gc.Ostats.Ndelmov++ +} + +func regtyp(a *obj.Addr) bool { + return a.Type == obj.TYPE_REG && (x86.REG_AX <= a.Reg && a.Reg <= x86.REG_R15 || x86.REG_X0 <= a.Reg && a.Reg <= x86.REG_X15) +} + +// movb elimination. +// movb is simulated by the linker +// when a register other than ax, bx, cx, dx +// is used, so rewrite to other instructions +// when possible. a movb into a register +// can smash the entire 32-bit register without +// causing any trouble. +// +// TODO: Using the Q forms here instead of the L forms +// seems unnecessary, and it makes the instructions longer. +func elimshortmov(g *gc.Graph) { + var p *obj.Prog + var r *gc.Flow + + for r = g.Start; r != nil; r = r.Link { + p = r.Prog + if regtyp(&p.To) { + switch p.As { + case x86.AINCB, + x86.AINCW: + p.As = x86.AINCQ + + case x86.ADECB, + x86.ADECW: + p.As = x86.ADECQ + + case x86.ANEGB, + x86.ANEGW: + p.As = x86.ANEGQ + + case x86.ANOTB, + x86.ANOTW: + p.As = x86.ANOTQ + } + + if regtyp(&p.From) || p.From.Type == obj.TYPE_CONST { + // move or artihmetic into partial register. + // from another register or constant can be movl. + // we don't switch to 64-bit arithmetic if it can + // change how the carry bit is set (and the carry bit is needed). + switch p.As { + case x86.AMOVB, + x86.AMOVW: + p.As = x86.AMOVQ + + case x86.AADDB, + x86.AADDW: + if !needc(p.Link) { + p.As = x86.AADDQ + } + + case x86.ASUBB, + x86.ASUBW: + if !needc(p.Link) { + p.As = x86.ASUBQ + } + + case x86.AMULB, + x86.AMULW: + p.As = x86.AMULQ + + case x86.AIMULB, + x86.AIMULW: + p.As = x86.AIMULQ + + case x86.AANDB, + x86.AANDW: + p.As = x86.AANDQ + + case x86.AORB, + x86.AORW: + p.As = x86.AORQ + + case x86.AXORB, + x86.AXORW: + p.As = x86.AXORQ + + case x86.ASHLB, + x86.ASHLW: + p.As = x86.ASHLQ + } + } else if p.From.Type != obj.TYPE_REG { + // explicit zero extension, but don't + // do that if source is a byte register + // (only AH can occur and it's forbidden). + switch p.As { + case x86.AMOVB: + p.As = x86.AMOVBQZX + + case x86.AMOVW: + p.As = x86.AMOVWQZX + } + } + } + } +} + +// is 'a' a register or constant? +func regconsttyp(a *obj.Addr) bool { + if regtyp(a) { + return true + } + switch a.Type { + case obj.TYPE_CONST, + obj.TYPE_FCONST, + obj.TYPE_SCONST, + obj.TYPE_ADDR: // TODO(rsc): Not all TYPE_ADDRs are constants. + return true + } + + return false +} + +// is reg guaranteed to be truncated by a previous L instruction? +func prevl(r0 *gc.Flow, reg int) bool { + var p *obj.Prog + var r *gc.Flow + var info gc.ProgInfo + + for r = gc.Uniqp(r0); r != nil; r = gc.Uniqp(r) { + p = r.Prog + if p.To.Type == obj.TYPE_REG && int(p.To.Reg) == reg { + proginfo(&info, p) + if info.Flags&gc.RightWrite != 0 { + if info.Flags&gc.SizeL != 0 { + return true + } + return false + } + } + } + + return false +} + +/* + * the idea is to substitute + * one register for another + * from one MOV to another + * MOV a, R0 + * ADD b, R0 / no use of R1 + * MOV R0, R1 + * would be converted to + * MOV a, R1 + * ADD b, R1 + * MOV R1, R0 + * hopefully, then the former or latter MOV + * will be eliminated by copy propagation. + */ +func subprop(r0 *gc.Flow) bool { + var p *obj.Prog + var info gc.ProgInfo + var v1 *obj.Addr + var v2 *obj.Addr + var r *gc.Flow + var t int + + if gc.Debug['P'] != 0 && gc.Debug['v'] != 0 { + fmt.Printf("subprop %v\n", r0.Prog) + } + p = r0.Prog + v1 = &p.From + if !regtyp(v1) { + if gc.Debug['P'] != 0 && gc.Debug['v'] != 0 { + fmt.Printf("\tnot regtype %v; return 0\n", gc.Ctxt.Dconv(v1)) + } + return false + } + + v2 = &p.To + if !regtyp(v2) { + if gc.Debug['P'] != 0 && gc.Debug['v'] != 0 { + fmt.Printf("\tnot regtype %v; return 0\n", gc.Ctxt.Dconv(v2)) + } + return false + } + + for r = gc.Uniqp(r0); r != nil; r = gc.Uniqp(r) { + if gc.Debug['P'] != 0 && gc.Debug['v'] != 0 { + fmt.Printf("\t? %v\n", r.Prog) + } + if gc.Uniqs(r) == nil { + if gc.Debug['P'] != 0 && gc.Debug['v'] != 0 { + fmt.Printf("\tno unique successor\n") + } + break + } + + p = r.Prog + if p.As == obj.AVARDEF || p.As == obj.AVARKILL { + continue + } + proginfo(&info, p) + if info.Flags&gc.Call != 0 { + if gc.Debug['P'] != 0 && gc.Debug['v'] != 0 { + fmt.Printf("\tfound %v; return 0\n", p) + } + return false + } + + if info.Reguse|info.Regset != 0 { + if gc.Debug['P'] != 0 && gc.Debug['v'] != 0 { + fmt.Printf("\tfound %v; return 0\n", p) + } + return false + } + + if (info.Flags&gc.Move != 0) && (info.Flags&(gc.SizeL|gc.SizeQ|gc.SizeF|gc.SizeD) != 0) && p.To.Type == v1.Type && p.To.Reg == v1.Reg { + goto gotit + } + + if copyau(&p.From, v2) || copyau(&p.To, v2) { + if gc.Debug['P'] != 0 && gc.Debug['v'] != 0 { + fmt.Printf("\tcopyau %v failed\n", gc.Ctxt.Dconv(v2)) + } + break + } + + if copysub(&p.From, v1, v2, 0) != 0 || copysub(&p.To, v1, v2, 0) != 0 { + if gc.Debug['P'] != 0 && gc.Debug['v'] != 0 { + fmt.Printf("\tcopysub failed\n") + } + break + } + } + + if gc.Debug['P'] != 0 && gc.Debug['v'] != 0 { + fmt.Printf("\tran off end; return 0\n") + } + return false + +gotit: + 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 && p.From.Reg == v2.Reg { + 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) + copysub(&p.To, v1, v2, 1) + if gc.Debug['P'] != 0 { + fmt.Printf("%v\n", r.Prog) + } + } + + t = 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 +} + +/* + * 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 F=0 + * (use v2 s/v2/v1/)* + * set v1 F=1 + * set v2 return success + */ +func copyprop(g *gc.Graph, r0 *gc.Flow) bool { + var p *obj.Prog + var v1 *obj.Addr + var v2 *obj.Addr + + if gc.Debug['P'] != 0 && gc.Debug['v'] != 0 { + fmt.Printf("copyprop %v\n", r0.Prog) + } + p = r0.Prog + v1 = &p.From + v2 = &p.To + if copyas(v1, v2) { + return true + } + gactive++ + return copy1(v1, v2, r0.S1, 0) +} + +func copy1(v1 *obj.Addr, v2 *obj.Addr, r *gc.Flow, f int) bool { + var t int + var p *obj.Prog + + 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("copy %v->%v f=%d\n", gc.Ctxt.Dconv(v1), gc.Ctxt.Dconv(v2), f) + } + 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 { + 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", gc.Ctxt.Dconv(v2), gc.Ctxt.Dconv(v1)) + } + 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 +} + +/* + * return + * 1 if v only used (and substitute), + * 2 if read-alter-rewrite + * 3 if set + * 4 if set and used + * 0 otherwise (not touched) + */ +func copyu(p *obj.Prog, v *obj.Addr, s *obj.Addr) int { + var info gc.ProgInfo + + switch p.As { + case obj.AJMP: + 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: + if s != nil { + return 1 + } + return 3 + + case obj.ACALL: + if x86.REGEXT != 0 /*TypeKind(100016)*/ && v.Type == obj.TYPE_REG && v.Reg <= x86.REGEXT && v.Reg > exregoffset { + return 2 + } + if x86.REGARG >= 0 && v.Type == obj.TYPE_REG && v.Reg == x86.REGARG { + return 2 + } + if v.Type == p.From.Type && v.Reg == p.From.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 + + case obj.ATEXT: + if x86.REGARG >= 0 && v.Type == obj.TYPE_REG && v.Reg == x86.REGARG { + return 3 + } + return 0 + } + + if p.As == obj.AVARDEF || p.As == obj.AVARKILL { + return 0 + } + proginfo(&info, p) + + if (info.Reguse|info.Regset)&RtoB(int(v.Reg)) != 0 { + return 2 + } + + if info.Flags&gc.LeftAddr != 0 { + if copyas(&p.From, v) { + return 2 + } + } + + if info.Flags&(gc.RightRead|gc.RightWrite) == gc.RightRead|gc.RightWrite { + if copyas(&p.To, v) { + return 2 + } + } + + if info.Flags&gc.RightWrite != 0 { + if copyas(&p.To, v) { + if s != nil { + return copysub(&p.From, v, s, 1) + } + if copyau(&p.From, v) { + return 4 + } + return 3 + } + } + + if info.Flags&(gc.LeftAddr|gc.LeftRead|gc.LeftWrite|gc.RightAddr|gc.RightRead|gc.RightWrite) != 0 { + if s != nil { + if copysub(&p.From, v, s, 1) != 0 { + return 1 + } + return copysub(&p.To, v, s, 1) + } + + if copyau(&p.From, v) { + return 1 + } + if copyau(&p.To, v) { + return 1 + } + } + + return 0 +} + +/* + * direct reference, + * could be set/use depending on + * semantics + */ +func copyas(a *obj.Addr, v *obj.Addr) bool { + if x86.REG_AL <= a.Reg && a.Reg <= x86.REG_R15B { + gc.Fatal("use of byte register") + } + if x86.REG_AL <= v.Reg && v.Reg <= x86.REG_R15B { + gc.Fatal("use of byte register") + } + + if a.Type != v.Type || a.Name != v.Name || a.Reg != v.Reg { + return false + } + if regtyp(v) { + return true + } + if v.Type == obj.TYPE_MEM && (v.Name == obj.NAME_AUTO || v.Name == obj.NAME_PARAM) { + if v.Offset == a.Offset { + return true + } + } + return false +} + +func sameaddr(a *obj.Addr, v *obj.Addr) bool { + if a.Type != v.Type || a.Name != v.Name || a.Reg != v.Reg { + return false + } + if regtyp(v) { + return true + } + if v.Type == obj.TYPE_MEM && (v.Name == obj.NAME_AUTO || v.Name == obj.NAME_PARAM) { + if v.Offset == a.Offset { + return true + } + } + return false +} + +/* + * either direct or indirect + */ +func copyau(a *obj.Addr, v *obj.Addr) bool { + if copyas(a, v) { + if gc.Debug['P'] != 0 && gc.Debug['v'] != 0 { + fmt.Printf("\tcopyau: copyas returned 1\n") + } + return true + } + + if regtyp(v) { + if a.Type == obj.TYPE_MEM && a.Reg == v.Reg { + if gc.Debug['P'] != 0 && gc.Debug['v'] != 0 { + fmt.Printf("\tcopyau: found indir use - return 1\n") + } + return true + } + + if a.Index == v.Reg { + if gc.Debug['P'] != 0 && gc.Debug['v'] != 0 { + fmt.Printf("\tcopyau: found index use - return 1\n") + } + return true + } + } + + return false +} + +/* + * substitute s for v in a + * return failure to substitute + */ +func copysub(a *obj.Addr, v *obj.Addr, s *obj.Addr, f int) int { + var reg int + + if copyas(a, v) { + reg = int(s.Reg) + if reg >= x86.REG_AX && reg <= x86.REG_R15 || reg >= x86.REG_X0 && reg <= x86.REG_X0+15 { + if f != 0 { + a.Reg = int16(reg) + } + } + + return 0 + } + + if regtyp(v) { + reg = int(v.Reg) + if a.Type == obj.TYPE_MEM && int(a.Reg) == reg { + if (s.Reg == x86.REG_BP || s.Reg == x86.REG_R13) && a.Index != x86.REG_NONE { + return 1 /* can't use BP-base with index */ + } + if f != 0 { + a.Reg = s.Reg + } + } + + // return 0; + if int(a.Index) == reg { + if f != 0 { + a.Index = s.Reg + } + return 0 + } + + return 0 + } + + return 0 +} + +func conprop(r0 *gc.Flow) { + var r *gc.Flow + var p *obj.Prog + var p0 *obj.Prog + var t int + var v0 *obj.Addr + + p0 = r0.Prog + v0 = &p0.To + r = r0 + +loop: + r = gc.Uniqs(r) + if r == nil || r == r0 { + return + } + if gc.Uniqp(r) == nil { + return + } + + p = r.Prog + t = copyu(p, v0, nil) + switch t { + case 0, // miss + 1: // use + goto loop + + case 2, // rar + 4: // use and set + break + + case 3: // set + if p.As == p0.As { + if p.From.Type == p0.From.Type { + if p.From.Reg == p0.From.Reg { + if p.From.Node == p0.From.Node { + if p.From.Offset == p0.From.Offset { + if p.From.Scale == p0.From.Scale { + if p.From.Type == obj.TYPE_FCONST && p.From.U.Dval == p0.From.U.Dval { + if p.From.Index == p0.From.Index { + excise(r) + goto loop + } + } + } + } + } + } + } + } + } +} + +func smallindir(a *obj.Addr, reg *obj.Addr) bool { + return regtyp(reg) && a.Type == obj.TYPE_MEM && a.Reg == reg.Reg && a.Index == x86.REG_NONE && 0 <= a.Offset && a.Offset < 4096 +} + +func stackaddr(a *obj.Addr) bool { + return a.Type == obj.TYPE_REG && a.Reg == x86.REG_SP +} |