コード例 #1
0
ファイル: peep.go プロジェクト: glycerine/zygomys
// 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(r *gc.Flow) bool {
	p := r.Prog

	canSub := false
	switch p.As {
	case s390x.AFMOVS, s390x.AFMOVD, s390x.AMOVD:
		canSub = true
	default:
		for rr := gc.Uniqp(r); rr != nil; rr = gc.Uniqp(rr) {
			if gc.Uniqs(rr) == nil {
				break
			}
			switch copyu(rr.Prog, &p.From, nil) {
			case _Read, _None:
				continue
			}
			// write
			if rr.Prog.As == p.As {
				canSub = true
			}
			break
		}
	}
	if !canSub {
		return false
	}
	if copyas(&p.From, &p.To) {
		return true
	}

	gactive++
	return copy1(&p.From, &p.To, r.S1, 0)
}
コード例 #2
0
ファイル: peep.go プロジェクト: glycerine/zygomys
// 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. subprop returns true if it modified any instructions.
func subprop(r0 *gc.Flow) bool {
	p := r0.Prog
	v1 := &p.From
	if !isReg(v1) {
		return false
	}
	v2 := &p.To
	if !isReg(v2) {
		return false
	}
	cast := false
	switch p.As {
	case s390x.AMOVW, s390x.AMOVWZ,
		s390x.AMOVH, s390x.AMOVHZ,
		s390x.AMOVB, s390x.AMOVBZ:
		cast = true
	}
	for r := gc.Uniqp(r0); r != nil; r = gc.Uniqp(r) {
		if gc.Uniqs(r) == nil {
			break
		}
		p = r.Prog
		switch copyu(p, v1, nil) {
		case _Write, _ReadWriteDiff:
			if p.As == obj.ACALL {
				return false
			}
			if (!cast || p.As == r0.Prog.As) && p.To.Type == v1.Type && p.To.Reg == v1.Reg {
				copysub(&p.To, v1, v2)
				for r = gc.Uniqs(r); r != r0; r = gc.Uniqs(r) {
					p = r.Prog
					copysub(&p.From, v1, v2)
					copysub1(p, v1, v2)
					copysub(&p.To, v1, v2)
				}
				v1.Reg, v2.Reg = v2.Reg, v1.Reg
				return true
			}
			if cast {
				return false
			}
		case _ReadWriteSame:
			if cast {
				return false
			}
		}
		if copyu(p, v2, nil) != _None {
			return false
		}
	}
	return false
}
コード例 #3
0
ファイル: peep.go プロジェクト: glycerine/zygomys
// is reg guaranteed to be truncated by a previous L instruction?
func prevl(r0 *gc.Flow, reg int16) bool {
	for r := gc.Uniqp(r0); r != nil; r = gc.Uniqp(r) {
		p := r.Prog
		if p.To.Type == obj.TYPE_REG && p.To.Reg == reg {
			flags := progflags(p)
			if flags&gc.RightWrite != 0 {
				if flags&gc.SizeL != 0 {
					return true
				}
				return false
			}
		}
	}
	return false
}
コード例 #4
0
ファイル: peep.go プロジェクト: glycerine/zygomys
/*
 * findinc finds ADD instructions with a constant
 * argument which falls within the immed_12 range.
 */
func findinc(r *gc.Flow, r2 *gc.Flow, v *obj.Addr) *gc.Flow {
	var r1 *gc.Flow
	var p *obj.Prog

	for r1 = gc.Uniqs(r); r1 != nil && r1 != r2; r, r1 = r1, gc.Uniqs(r1) {
		if gc.Uniqp(r1) != r {
			return nil
		}
		switch copyu(r1.Prog, v, nil) {
		case 0: /* not touched */
			continue

		case 4: /* set and used */
			p = r1.Prog

			if p.As == arm.AADD {
				if isdconst(&p.From) {
					if p.From.Offset > -4096 && p.From.Offset < 4096 {
						return r1
					}
				}
			}
			fallthrough

		default:
			return nil
		}
	}

	return nil
}
コード例 #5
0
ファイル: peep.go プロジェクト: glycerine/zygomys
// removeLoadHitStores trys to remove loads that take place
// immediately after a store to the same location. Returns
// true if load-hit-stores were removed.
//
// For example:
// 	MOVD	R1, 0(R15)
// 	MOVD	0(R15), R2
// Would become:
// 	MOVD	R1, 0(R15)
// 	MOVD	R1, R2
func removeLoadHitStores(r *gc.Flow) int {
	n := 0
	for ; r != nil; r = r.Link {
		p := r.Prog
		if !isStore(p) {
			continue
		}
		for rr := gc.Uniqs(r); rr != nil; rr = gc.Uniqs(rr) {
			pp := rr.Prog
			if gc.Uniqp(rr) == nil {
				break
			}
			if pp.As == obj.ANOP {
				continue
			}
			if isLoad(pp) && sameStackMem(&p.To, &pp.From) {
				if size(p.As) >= size(pp.As) && isGPR(&p.From) == isGPR(&pp.To) {
					pp.From = p.From
				}
			}
			if !isMove(pp) || isStore(pp) {
				break
			}
			if copyau(&p.From, &pp.To) {
				break
			}
		}
	}
	return n
}
コード例 #6
0
ファイル: peep.go プロジェクト: glycerine/zygomys
/*
 * findpre returns the last instruction mentioning v
 * before r. It must be a set, and there must be
 * a unique path from that instruction to r.
 */
func findpre(r *gc.Flow, v *obj.Addr) *gc.Flow {
	var r1 *gc.Flow

	for r1 = gc.Uniqp(r); r1 != nil; r, r1 = r1, gc.Uniqp(r1) {
		if gc.Uniqs(r1) != r {
			return nil
		}
		switch copyu(r1.Prog, v, nil) {
		case 1, /* used */
			2: /* read-alter-rewrite */
			return nil

		case 3, /* set */
			4: /* set and used */
			return r1
		}
	}

	return nil
}
コード例 #7
0
ファイル: peep.go プロジェクト: glycerine/zygomys
func conprop(r0 *gc.Flow) {
	var p *obj.Prog

	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
	switch copyu(p, v0, nil) {
	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.Val.(float64) == p0.From.Val.(float64) {
									if p.From.Index == p0.From.Index {
										excise(r)
										goto loop
									}
								}
							}
						}
					}
				}
			}
		}
	}
}
コード例 #8
0
ファイル: peep.go プロジェクト: glycerine/zygomys
// copy1 replaces uses of v2 with v1 starting at r and returns true if
// all uses were rewritten.
func copy1(v1 *obj.Addr, v2 *obj.Addr, r *gc.Flow, f int) bool {
	if uint32(r.Active) == gactive {
		return true
	}
	r.Active = int32(gactive)
	for ; r != nil; r = r.S1 {
		p := r.Prog
		if f == 0 && gc.Uniqp(r) == nil {
			// Multiple predecessors; conservatively
			// assume v1 was set on other path
			f = 1
		}
		t := copyu(p, v2, nil)
		switch t {
		case _ReadWriteSame:
			return false
		case _Write:
			return true
		case _Read, _ReadWriteDiff:
			if f != 0 {
				return false
			}
			if copyu(p, v2, v1) != 0 {
				return false
			}
			if t == _ReadWriteDiff {
				return true
			}
		}
		if f == 0 {
			switch copyu(p, v1, nil) {
			case _ReadWriteSame, _ReadWriteDiff, _Write:
				f = 1
			}
		}
		if r.S2 != nil {
			if !copy1(v1, v2, r.S2, f) {
				return false
			}
		}
	}
	return true
}
コード例 #9
0
ファイル: peep.go プロジェクト: glycerine/zygomys
/*
 * The idea is to remove redundant constants.
 *	$c1->v1
 *	($c1->v2 s/$c1/v1)*
 *	set v1  return
 * The v1->v2 should be eliminated by copy propagation.
 */
func constprop(c1 *obj.Addr, v1 *obj.Addr, r *gc.Flow) {
	if gc.Debug['P'] != 0 {
		fmt.Printf("constprop %v->%v\n", gc.Ctxt.Dconv(c1), gc.Ctxt.Dconv(v1))
	}
	var p *obj.Prog
	for ; r != nil; r = r.S1 {
		p = r.Prog
		if gc.Debug['P'] != 0 {
			fmt.Printf("%v", p)
		}
		if gc.Uniqp(r) == nil {
			if gc.Debug['P'] != 0 {
				fmt.Printf("; merge; return\n")
			}
			return
		}

		if p.As == arm.AMOVW && copyas(&p.From, c1) {
			if gc.Debug['P'] != 0 {
				fmt.Printf("; sub%v/%v", gc.Ctxt.Dconv(&p.From), gc.Ctxt.Dconv(v1))
			}
			p.From = *v1
		} else if copyu(p, v1, nil) > 1 {
			if gc.Debug['P'] != 0 {
				fmt.Printf("; %vset; return\n", gc.Ctxt.Dconv(v1))
			}
			return
		}

		if gc.Debug['P'] != 0 {
			fmt.Printf("\n")
		}
		if r.S2 != nil {
			constprop(c1, v1, r.S2)
		}
	}
}
コード例 #10
0
ファイル: peep.go プロジェクト: glycerine/zygomys
/*
 * 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 := r0.Prog
	v1 := &p.From
	if !regtyp(v1) {
		return false
	}
	v2 := &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, true)
					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, true)
						copysub1(p, v1, v2, true)
						copysub(&p.To, v1, v2, true)
						if gc.Debug['P'] != 0 {
							fmt.Printf("%v\n", r.Prog)
						}
					}

					v1.Reg, v2.Reg = v2.Reg, v1.Reg
					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, false) || copysub1(p, v1, v2, false) || copysub(&p.To, v1, v2, false) {
			break
		}
	}

	return false
}
コード例 #11
0
ファイル: peep.go プロジェクト: glycerine/zygomys
func pushback(r0 *gc.Flow) {
	var r *gc.Flow

	var b *gc.Flow
	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 !(isReg(&p.From) || isConst(&p.From)) || !isReg(&p.To) {
				break
			}
			if copyu(p, &p0.To, nil) != _None || copyu(p0, &p.To, nil) != _None {
				break
			}
		}

		if p.As == obj.ACALL {
			break
		}
		b = r
	}

	if b == nil {
		if gc.Debug['P'] != 0 && gc.Debug['v'] != 0 {
			fmt.Printf("no pushback: %v\n", r0.Prog)
			if r != nil {
				fmt.Printf("\t%v [%v]\n", r.Prog, gc.Uniqs(r) != nil)
			}
		}

		return
	}

	if gc.Debug['P'] != 0 && 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
		p0.From3 = p.From3
		p0.Reg = p.Reg
		p0.RegTo2 = p.RegTo2
		if r == b {
			break
		}
	}

	p0 = r.Prog
	p0.As = t.As
	p0.Lineno = t.Lineno
	p0.From = t.From
	p0.To = t.To
	p0.From3 = t.From3
	p0.Reg = t.Reg
	p0.RegTo2 = t.RegTo2

	if gc.Debug['P'] != 0 && 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
			}
		}
	}
}
コード例 #12
0
ファイル: peep.go プロジェクト: glycerine/zygomys
/*
 * 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 {
	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
		}
		if p.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 p.Info.Reguse|p.Info.Regset != 0 {
			if gc.Debug['P'] != 0 && gc.Debug['v'] != 0 {
				fmt.Printf("\tfound %v; return 0\n", p)
			}
			return false
		}

		if (p.Info.Flags&gc.Move != 0) && (p.Info.Flags&(gc.SizeL|gc.SizeQ|gc.SizeF|gc.SizeD) != 0) && p.To.Type == v1.Type && p.To.Reg == v1.Reg {
			copysub(&p.To, v1, v2, true)
			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, true)
				copysub(&p.To, v1, v2, true)
				if gc.Debug['P'] != 0 {
					fmt.Printf("%v\n", r.Prog)
				}
			}

			v1.Reg, v2.Reg = v2.Reg, v1.Reg
			if gc.Debug['P'] != 0 {
				fmt.Printf("%v last\n", r.Prog)
			}
			return true
		}

		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, false) || copysub(&p.To, v1, v2, false) {
			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
}
コード例 #13
0
ファイル: peep.go プロジェクト: glycerine/zygomys
func pushback(r0 *gc.Flow) {
	var r *gc.Flow
	var p *obj.Prog

	var b *gc.Flow
	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['P'] != 0 && gc.Debug['v'] != 0 {
			fmt.Printf("no pushback: %v\n", r0.Prog)
			if r != nil {
				fmt.Printf("\t%v [%v]\n", r.Prog, gc.Uniqs(r) != nil)
			}
		}

		return
	}

	if gc.Debug['P'] != 0 && 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['P'] != 0 && 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
			}
		}
	}
}
コード例 #14
0
ファイル: peep.go プロジェクト: glycerine/zygomys
/*
 * ASLL x,y,w
 * .. (not use w, not set x y w)
 * AXXX w,a,b (a != w)
 * .. (not use w)
 * (set w)
 * ----------- changed to
 * ..
 * AXXX (x<<y),a,b
 * ..
 */
func shiftprop(r *gc.Flow) bool {
	p := r.Prog
	if p.To.Type != obj.TYPE_REG {
		if gc.Debug['P'] != 0 {
			fmt.Printf("\tBOTCH: result not reg; FAILURE\n")
		}
		return false
	}

	n := p.To.Reg
	var a obj.Addr
	if p.Reg != 0 && p.Reg != p.To.Reg {
		a.Type = obj.TYPE_REG
		a.Reg = p.Reg
	}

	if gc.Debug['P'] != 0 {
		fmt.Printf("shiftprop\n%v", p)
	}
	r1 := r
	var p1 *obj.Prog
	for {
		/* find first use of shift result; abort if shift operands or result are changed */
		r1 = gc.Uniqs(r1)

		if r1 == nil {
			if gc.Debug['P'] != 0 {
				fmt.Printf("\tbranch; FAILURE\n")
			}
			return false
		}

		if gc.Uniqp(r1) == nil {
			if gc.Debug['P'] != 0 {
				fmt.Printf("\tmerge; FAILURE\n")
			}
			return false
		}

		p1 = r1.Prog
		if gc.Debug['P'] != 0 {
			fmt.Printf("\n%v", p1)
		}
		switch copyu(p1, &p.To, nil) {
		case 0: /* not used or set */
			if (p.From.Type == obj.TYPE_REG && copyu(p1, &p.From, nil) > 1) || (a.Type == obj.TYPE_REG && copyu(p1, &a, nil) > 1) {
				if gc.Debug['P'] != 0 {
					fmt.Printf("\targs modified; FAILURE\n")
				}
				return false
			}

			continue
		case 3: /* set, not used */
			{
				if gc.Debug['P'] != 0 {
					fmt.Printf("\tBOTCH: noref; FAILURE\n")
				}
				return false
			}
		}

		break
	}

	/* check whether substitution can be done */
	switch p1.As {
	default:
		if gc.Debug['P'] != 0 {
			fmt.Printf("\tnon-dpi; FAILURE\n")
		}
		return false

	case arm.AAND,
		arm.AEOR,
		arm.AADD,
		arm.AADC,
		arm.AORR,
		arm.ASUB,
		arm.ASBC,
		arm.ARSB,
		arm.ARSC:
		if p1.Reg == n || (p1.Reg == 0 && p1.To.Type == obj.TYPE_REG && p1.To.Reg == n) {
			if p1.From.Type != obj.TYPE_REG {
				if gc.Debug['P'] != 0 {
					fmt.Printf("\tcan't swap; FAILURE\n")
				}
				return false
			}

			p1.Reg = p1.From.Reg
			p1.From.Reg = n
			switch p1.As {
			case arm.ASUB:
				p1.As = arm.ARSB

			case arm.ARSB:
				p1.As = arm.ASUB

			case arm.ASBC:
				p1.As = arm.ARSC

			case arm.ARSC:
				p1.As = arm.ASBC
			}

			if gc.Debug['P'] != 0 {
				fmt.Printf("\t=>%v", p1)
			}
		}
		fallthrough

	case arm.ABIC,
		arm.ATST,
		arm.ACMP,
		arm.ACMN:
		if p1.Reg == n {
			if gc.Debug['P'] != 0 {
				fmt.Printf("\tcan't swap; FAILURE\n")
			}
			return false
		}

		if p1.Reg == 0 && p1.To.Reg == n {
			if gc.Debug['P'] != 0 {
				fmt.Printf("\tshift result used twice; FAILURE\n")
			}
			return false
		}

		//	case AMVN:
		if p1.From.Type == obj.TYPE_SHIFT {
			if gc.Debug['P'] != 0 {
				fmt.Printf("\tshift result used in shift; FAILURE\n")
			}
			return false
		}

		if p1.From.Type != obj.TYPE_REG || p1.From.Reg != n {
			if gc.Debug['P'] != 0 {
				fmt.Printf("\tBOTCH: where is it used?; FAILURE\n")
			}
			return false
		}
	}

	/* check whether shift result is used subsequently */
	p2 := p1

	if p1.To.Reg != n {
		var p1 *obj.Prog
		for {
			r1 = gc.Uniqs(r1)
			if r1 == nil {
				if gc.Debug['P'] != 0 {
					fmt.Printf("\tinconclusive; FAILURE\n")
				}
				return false
			}

			p1 = r1.Prog
			if gc.Debug['P'] != 0 {
				fmt.Printf("\n%v", p1)
			}
			switch copyu(p1, &p.To, nil) {
			case 0: /* not used or set */
				continue

			case 3: /* set, not used */
				break

			default: /* used */
				if gc.Debug['P'] != 0 {
					fmt.Printf("\treused; FAILURE\n")
				}
				return false
			}

			break
		}
	}

	/* make the substitution */
	p2.From.Reg = 0
	o := p.Reg
	if o == 0 {
		o = p.To.Reg
	}
	o &= 15

	switch p.From.Type {
	case obj.TYPE_CONST:
		o |= int16(p.From.Offset&0x1f) << 7

	case obj.TYPE_REG:
		o |= 1<<4 | (p.From.Reg&15)<<8
	}

	switch p.As {
	case arm.ASLL:
		o |= 0 << 5

	case arm.ASRL:
		o |= 1 << 5

	case arm.ASRA:
		o |= 2 << 5
	}

	p2.From = obj.Addr{}
	p2.From.Type = obj.TYPE_SHIFT
	p2.From.Offset = int64(o)
	if gc.Debug['P'] != 0 {
		fmt.Printf("\t=>%v\tSUCCEED\n", p2)
	}
	return true
}
コード例 #15
0
ファイル: peep.go プロジェクト: glycerine/zygomys
// fuseClear merges memory clear operations.
//
// Looks for this pattern (sequence of clears):
// 	MOVD	R0, n(R15)
// 	MOVD	R0, n+8(R15)
// 	MOVD	R0, n+16(R15)
// Replaces with:
//	CLEAR	$24, n(R15)
func fuseClear(r *gc.Flow) int {
	n := 0
	var align int64
	var clear *obj.Prog
	for ; r != nil; r = r.Link {
		// If there is a branch into the instruction stream then
		// we can't fuse into previous instructions.
		if gc.Uniqp(r) == nil {
			clear = nil
		}

		p := r.Prog
		if p.As == obj.ANOP {
			continue
		}
		if p.As == s390x.AXC {
			if p.From.Reg == p.To.Reg && p.From.Offset == p.To.Offset {
				// TODO(mundaym): merge clears?
				p.As = s390x.ACLEAR
				p.From.Offset = p.From3.Offset
				p.From3 = nil
				p.From.Type = obj.TYPE_CONST
				p.From.Reg = 0
				clear = p
			} else {
				clear = nil
			}
			continue
		}

		// Is our source a constant zero?
		if !isZero(&p.From) {
			clear = nil
			continue
		}

		// Are we moving to memory?
		if p.To.Type != obj.TYPE_MEM ||
			p.To.Index != 0 ||
			p.To.Offset >= 4096 ||
			!(p.To.Name == obj.NAME_NONE || p.To.Name == obj.NAME_AUTO || p.To.Name == obj.NAME_PARAM) {
			clear = nil
			continue
		}

		size := int64(0)
		switch p.As {
		default:
			clear = nil
			continue
		case s390x.AMOVB, s390x.AMOVBZ:
			size = 1
		case s390x.AMOVH, s390x.AMOVHZ:
			size = 2
		case s390x.AMOVW, s390x.AMOVWZ:
			size = 4
		case s390x.AMOVD:
			size = 8
		}

		// doubleword aligned clears should be kept doubleword
		// aligned
		if (size == 8 && align != 8) || (size != 8 && align == 8) {
			clear = nil
		}

		if clear != nil &&
			clear.To.Reg == p.To.Reg &&
			clear.To.Name == p.To.Name &&
			clear.To.Node == p.To.Node &&
			clear.To.Sym == p.To.Sym {

			min := clear.To.Offset
			max := clear.To.Offset + clear.From.Offset

			// previous clear is already clearing this region
			if min <= p.To.Offset && max >= p.To.Offset+size {
				excise(r)
				n++
				continue
			}

			// merge forwards
			if max == p.To.Offset {
				clear.From.Offset += size
				excise(r)
				n++
				continue
			}

			// merge backwards
			if min-size == p.To.Offset {
				clear.From.Offset += size
				clear.To.Offset -= size
				excise(r)
				n++
				continue
			}
		}

		// transform into clear
		p.From.Type = obj.TYPE_CONST
		p.From.Offset = size
		p.From.Reg = 0
		p.As = s390x.ACLEAR
		clear = p
		align = size
	}
	return n
}
コード例 #16
0
ファイル: peep.go プロジェクト: glycerine/zygomys
// castPropagation tries to eliminate unecessary casts.
//
// For example:
// 	MOVHZ	R1, R2     // uint16
//	MOVB	R2, 0(R15) // int8
// Can be simplified to:
//	MOVB	R1, 0(R15)
func castPropagation(r *gc.Flow) int {
	n := 0
	for ; r != nil; r = r.Link {
		p := r.Prog
		if !isMove(p) || !isGPR(&p.To) {
			continue
		}

		// r is a move with a destination register
		var move *gc.Flow
		for rr := gc.Uniqs(r); rr != nil; rr = gc.Uniqs(rr) {
			if gc.Uniqp(rr) == nil {
				// branch target: leave alone
				break
			}
			pp := rr.Prog
			if isMove(pp) && copyas(&pp.From, &p.To) {
				if pp.To.Type == obj.TYPE_MEM {
					if p.From.Type == obj.TYPE_MEM ||
						p.From.Type == obj.TYPE_ADDR {
						break
					}
					if p.From.Type == obj.TYPE_CONST &&
						int64(int16(p.From.Offset)) != p.From.Offset {
						break
					}
				}
				move = rr
				break
			}
			if pp.As == obj.ANOP {
				continue
			}
			break
		}
		if move == nil {
			continue
		}

		// we have a move that reads from our destination reg, check if any future
		// instructions also read from the reg
		mp := move.Prog
		if !copyas(&mp.From, &mp.To) {
			safe := false
			for rr := gc.Uniqs(move); rr != nil; rr = gc.Uniqs(rr) {
				if gc.Uniqp(rr) == nil {
					break
				}
				switch copyu(rr.Prog, &p.To, nil) {
				case _None:
					continue
				case _Write:
					safe = true
				}
				break
			}
			if !safe {
				continue
			}
		}

		// at this point we have something like:
		// MOV* const/mem/reg, reg
		// MOV* reg, reg/mem
		// now check if this is a cast that cannot be forward propagated
		execute := false
		if p.As == mp.As || isZero(&p.From) || size(p.As) == size(mp.As) {
			execute = true
		} else if isGPR(&p.From) && size(p.As) >= size(mp.As) {
			execute = true
		}

		if execute {
			mp.From = p.From
			excise(r)
			n++
		}
	}
	return n
}
コード例 #17
0
ファイル: peep.go プロジェクト: glycerine/zygomys
// fuseMultiple merges memory loads and stores into load multiple and
// store multiple operations.
//
// Looks for this pattern (sequence of loads or stores):
// 	MOVD	R1, 0(R15)
//	MOVD	R2, 8(R15)
//	MOVD	R3, 16(R15)
// Replaces with:
//	STMG	R1, R3, 0(R15)
func fuseMultiple(r *gc.Flow) int {
	n := 0
	var fused *obj.Prog
	for ; r != nil; r = r.Link {
		// If there is a branch into the instruction stream then
		// we can't fuse into previous instructions.
		if gc.Uniqp(r) == nil {
			fused = nil
		}

		p := r.Prog

		isStore := isGPR(&p.From) && isBDMem(&p.To)
		isLoad := isGPR(&p.To) && isBDMem(&p.From)

		// are we a candidate?
		size := int64(0)
		switch p.As {
		default:
			fused = nil
			continue
		case obj.ANOP:
			// skip over nops
			continue
		case s390x.AMOVW, s390x.AMOVWZ:
			size = 4
			// TODO(mundaym): 32-bit load multiple is currently not supported
			// as it requires sign/zero extension.
			if !isStore {
				fused = nil
				continue
			}
		case s390x.AMOVD:
			size = 8
			if !isLoad && !isStore {
				fused = nil
				continue
			}
		}

		// If we merge two loads/stores with different source/destination Nodes
		// then we will lose a reference the second Node which means that the
		// compiler might mark the Node as unused and free its slot on the stack.
		// TODO(mundaym): allow this by adding a dummy reference to the Node.
		if fused == nil ||
			fused.From.Node != p.From.Node ||
			fused.From.Type != p.From.Type ||
			fused.To.Node != p.To.Node ||
			fused.To.Type != p.To.Type {
			fused = p
			continue
		}

		// check two addresses
		ca := func(a, b *obj.Addr, offset int64) bool {
			return a.Reg == b.Reg && a.Offset+offset == b.Offset &&
				a.Sym == b.Sym && a.Name == b.Name
		}

		switch fused.As {
		default:
			fused = p
		case s390x.AMOVW, s390x.AMOVWZ:
			if size == 4 && fused.From.Reg+1 == p.From.Reg && ca(&fused.To, &p.To, 4) {
				fused.As = s390x.ASTMY
				fused.Reg = p.From.Reg
				excise(r)
				n++
			} else {
				fused = p
			}
		case s390x.AMOVD:
			if size == 8 && fused.From.Reg+1 == p.From.Reg && ca(&fused.To, &p.To, 8) {
				fused.As = s390x.ASTMG
				fused.Reg = p.From.Reg
				excise(r)
				n++
			} else if size == 8 && fused.To.Reg+1 == p.To.Reg && ca(&fused.From, &p.From, 8) {
				fused.As = s390x.ALMG
				fused.Reg = fused.To.Reg
				fused.To.Reg = p.To.Reg
				excise(r)
				n++
			} else {
				fused = p
			}
		case s390x.ASTMG, s390x.ASTMY:
			if (fused.As == s390x.ASTMY && size != 4) ||
				(fused.As == s390x.ASTMG && size != 8) {
				fused = p
				continue
			}
			offset := size * int64(fused.Reg-fused.From.Reg+1)
			if fused.Reg+1 == p.From.Reg && ca(&fused.To, &p.To, offset) {
				fused.Reg = p.From.Reg
				excise(r)
				n++
			} else {
				fused = p
			}
		case s390x.ALMG:
			offset := 8 * int64(fused.To.Reg-fused.Reg+1)
			if size == 8 && fused.To.Reg+1 == p.To.Reg && ca(&fused.From, &p.From, offset) {
				fused.To.Reg = p.To.Reg
				excise(r)
				n++
			} else {
				fused = p
			}
		}
	}
	return n
}
コード例 #18
0
ファイル: peep.go プロジェクト: glycerine/zygomys
/*
 * 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 {
	p := r0.Prog
	v1 := &p.From
	if !regtyp(v1) {
		return false
	}
	v2 := &p.To
	if !regtyp(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 {
			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.Reguse|p.Info.Regset != 0 {
			return false
		}

		if (p.Info.Flags&gc.Move != 0) && (p.Info.Flags&(gc.SizeL|gc.SizeQ|gc.SizeF|gc.SizeD) != 0) && p.To.Type == v1.Type && p.To.Reg == v1.Reg {
			copysub(&p.To, v1, v2, true)
			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, true)
				copysub(&p.To, v1, v2, true)
				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
		}

		if copyau(&p.From, v2) || copyau(&p.To, v2) {
			break
		}
		if copysub(&p.From, v1, v2, false) || copysub(&p.To, v1, v2, false) {
			break
		}
	}

	return false
}
コード例 #19
0
ファイル: peep.go プロジェクト: glycerine/zygomys
// fuseOpMoves looks for moves following 2-operand operations and trys to merge them into
// a 3-operand operation.
//
// For example:
//	ADD R1, R2
//	MOVD R2, R3
// might become
//	ADD R1, R2, R3
func fuseOpMoves(r *gc.Flow) int {
	n := 0
	for ; r != nil; r = r.Link {
		p := r.Prog
		switch p.As {
		case s390x.AADD:
		case s390x.ASUB:
			if isConst(&p.From) && int64(int16(p.From.Offset)) != p.From.Offset {
				continue
			}
		case s390x.ASLW,
			s390x.ASRW,
			s390x.ASRAW,
			s390x.ASLD,
			s390x.ASRD,
			s390x.ASRAD,
			s390x.ARLL,
			s390x.ARLLG:
			// ok - p.From will be a reg or a constant
		case s390x.AOR,
			s390x.AORN,
			s390x.AAND,
			s390x.AANDN,
			s390x.ANAND,
			s390x.ANOR,
			s390x.AXOR,
			s390x.AMULLW,
			s390x.AMULLD:
			if isConst(&p.From) {
				// these instructions can either use 3 register form
				// or have an immediate but not both
				continue
			}
		default:
			continue
		}

		if p.Reg != 0 && p.Reg != p.To.Reg {
			continue
		}

		var move *gc.Flow
		rr := gc.Uniqs(r)
		for {
			if rr == nil || gc.Uniqp(rr) == nil || rr == r {
				break
			}
			pp := rr.Prog
			switch copyu(pp, &p.To, nil) {
			case _None:
				rr = gc.Uniqs(rr)
				continue
			case _Read:
				if move == nil && pp.As == s390x.AMOVD && isGPR(&pp.From) && isGPR(&pp.To) {
					move = rr
					rr = gc.Uniqs(rr)
					continue
				}
			case _Write:
				if move == nil {
					// dead code
					excise(r)
					n++
				} else {
					for prev := gc.Uniqp(move); prev != r; prev = gc.Uniqp(prev) {
						if copyu(prev.Prog, &move.Prog.To, nil) != 0 {
							move = nil
							break
						}
					}
					if move == nil {
						break
					}
					p.Reg, p.To.Reg = p.To.Reg, move.Prog.To.Reg
					excise(move)
					n++

					// clean up
					if p.From.Reg == p.To.Reg && isCommutative(p.As) {
						p.From.Reg, p.Reg = p.Reg, 0
					}
					if p.To.Reg == p.Reg {
						p.Reg = 0
					}
					// we could try again if p has become a 2-operand op
					// but in testing nothing extra was extracted
				}
			}
			break
		}
	}
	return n
}
コード例 #20
0
ファイル: peep.go プロジェクト: glycerine/zygomys
func peep(firstp *obj.Prog) {
	g := gc.Flowstart(firstp, nil)
	if g == nil {
		return
	}
	gactive = 0

	var p *obj.Prog
	var r *gc.Flow
	var t obj.As
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(austin) Handle smaller moves.  arm and amd64
		// distinguish between moves that 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 == ppc64.AMOVD || p.As == ppc64.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++
						}
					}
				}

				// Convert uses to $0 to uses of R0 and
				// propagate R0
				if regzer(&p.From) {
					if p.To.Type == obj.TYPE_REG {
						p.From.Type = obj.TYPE_REG
						p.From.Reg = ppc64.REGZERO
						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 := g.Start; r != nil; r = r.Link {
		p = r.Prog
		switch p.As {
		default:
			continue

		case ppc64.AMOVH,
			ppc64.AMOVHZ,
			ppc64.AMOVB,
			ppc64.AMOVBZ,
			ppc64.AMOVW,
			ppc64.AMOVWZ:
			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 */
	}

	/*
	 * look for OP x,y,R; CMP R, $0 -> OPCC x,y,R
	 * when OP can set condition codes correctly
	 */
	for r := g.Start; r != nil; r = r.Link {
		p = r.Prog
		switch p.As {
		case ppc64.ACMP,
			ppc64.ACMPW: /* always safe? */
			if !regzer(&p.To) {
				continue
			}
			r1 = r.S1
			if r1 == nil {
				continue
			}
			switch r1.Prog.As {
			default:
				continue

				/* the conditions can be complex and these are currently little used */
			case ppc64.ABCL,
				ppc64.ABC:
				continue

			case ppc64.ABEQ,
				ppc64.ABGE,
				ppc64.ABGT,
				ppc64.ABLE,
				ppc64.ABLT,
				ppc64.ABNE,
				ppc64.ABVC,
				ppc64.ABVS:
				break
			}

			r1 = r
			for {
				r1 = gc.Uniqp(r1)
				if r1 == nil || r1.Prog.As != obj.ANOP {
					break
				}
			}

			if r1 == nil {
				continue
			}
			p1 = r1.Prog
			if p1.To.Type != obj.TYPE_REG || p1.To.Reg != p.From.Reg {
				continue
			}
			switch p1.As {
			/* irregular instructions */
			case ppc64.ASUB,
				ppc64.AADD,
				ppc64.AXOR,
				ppc64.AOR:
				if p1.From.Type == obj.TYPE_CONST || p1.From.Type == obj.TYPE_ADDR {
					continue
				}
			}

			switch p1.As {
			default:
				continue

			case ppc64.AMOVW,
				ppc64.AMOVD:
				if p1.From.Type != obj.TYPE_REG {
					continue
				}
				continue

			case ppc64.AANDCC,
				ppc64.AANDNCC,
				ppc64.AORCC,
				ppc64.AORNCC,
				ppc64.AXORCC,
				ppc64.ASUBCC,
				ppc64.ASUBECC,
				ppc64.ASUBMECC,
				ppc64.ASUBZECC,
				ppc64.AADDCC,
				ppc64.AADDCCC,
				ppc64.AADDECC,
				ppc64.AADDMECC,
				ppc64.AADDZECC,
				ppc64.ARLWMICC,
				ppc64.ARLWNMCC,
				/* don't deal with floating point instructions for now */
				/*
					case AFABS:
					case AFADD:
					case AFADDS:
					case AFCTIW:
					case AFCTIWZ:
					case AFDIV:
					case AFDIVS:
					case AFMADD:
					case AFMADDS:
					case AFMOVD:
					case AFMSUB:
					case AFMSUBS:
					case AFMUL:
					case AFMULS:
					case AFNABS:
					case AFNEG:
					case AFNMADD:
					case AFNMADDS:
					case AFNMSUB:
					case AFNMSUBS:
					case AFRSP:
					case AFSUB:
					case AFSUBS:
					case ACNTLZW:
					case AMTFSB0:
					case AMTFSB1:
				*/
				ppc64.AADD,
				ppc64.AADDV,
				ppc64.AADDC,
				ppc64.AADDCV,
				ppc64.AADDME,
				ppc64.AADDMEV,
				ppc64.AADDE,
				ppc64.AADDEV,
				ppc64.AADDZE,
				ppc64.AADDZEV,
				ppc64.AAND,
				ppc64.AANDN,
				ppc64.ADIVW,
				ppc64.ADIVWV,
				ppc64.ADIVWU,
				ppc64.ADIVWUV,
				ppc64.ADIVD,
				ppc64.ADIVDV,
				ppc64.ADIVDU,
				ppc64.ADIVDUV,
				ppc64.AEQV,
				ppc64.AEXTSB,
				ppc64.AEXTSH,
				ppc64.AEXTSW,
				ppc64.AMULHW,
				ppc64.AMULHWU,
				ppc64.AMULLW,
				ppc64.AMULLWV,
				ppc64.AMULHD,
				ppc64.AMULHDU,
				ppc64.AMULLD,
				ppc64.AMULLDV,
				ppc64.ANAND,
				ppc64.ANEG,
				ppc64.ANEGV,
				ppc64.ANOR,
				ppc64.AOR,
				ppc64.AORN,
				ppc64.AREM,
				ppc64.AREMV,
				ppc64.AREMU,
				ppc64.AREMUV,
				ppc64.AREMD,
				ppc64.AREMDV,
				ppc64.AREMDU,
				ppc64.AREMDUV,
				ppc64.ARLWMI,
				ppc64.ARLWNM,
				ppc64.ASLW,
				ppc64.ASRAW,
				ppc64.ASRW,
				ppc64.ASLD,
				ppc64.ASRAD,
				ppc64.ASRD,
				ppc64.ASUB,
				ppc64.ASUBV,
				ppc64.ASUBC,
				ppc64.ASUBCV,
				ppc64.ASUBME,
				ppc64.ASUBMEV,
				ppc64.ASUBE,
				ppc64.ASUBEV,
				ppc64.ASUBZE,
				ppc64.ASUBZEV,
				ppc64.AXOR:
				t = variant2as(p1.As, as2variant(p1.As)|V_CC)
			}

			if gc.Debug['D'] != 0 {
				fmt.Printf("cmp %v; %v -> ", p1, p)
			}
			p1.As = t
			if gc.Debug['D'] != 0 {
				fmt.Printf("%v\n", p1)
			}
			excise(r)
			continue
		}
	}

ret:
	gc.Flowend(g)
}
コード例 #21
0
ファイル: peep.go プロジェクト: glycerine/zygomys
// constantPropagation removes redundant constant copies.
func constantPropagation(r *gc.Flow) int {
	n := 0
	// find MOV $con,R followed by
	// another MOV $con,R without
	// setting R in the interim
	for ; r != nil; r = r.Link {
		p := r.Prog
		if isMove(p) {
			if !isReg(&p.To) {
				continue
			}
			if !isConst(&p.From) {
				continue
			}
		} else {
			continue
		}

		rr := r
		for {
			rr = gc.Uniqs(rr)
			if rr == nil || rr == r {
				break
			}
			if gc.Uniqp(rr) == nil {
				break
			}

			pp := rr.Prog
			t := copyu(pp, &p.To, nil)
			switch t {
			case _None:
				continue
			case _Read:
				if !isGPR(&pp.From) || !isMove(pp) {
					continue
				}
				if p.From.Type == obj.TYPE_CONST {
					v := applyCast(p.As, p.From.Offset)
					if isGPR(&pp.To) {
						if int64(int32(v)) == v || ((v>>32)<<32) == v {
							pp.From.Reg = 0
							pp.From.Offset = v
							pp.From.Type = obj.TYPE_CONST
							n++
						}
					} else if int64(int16(v)) == v {
						pp.From.Reg = 0
						pp.From.Offset = v
						pp.From.Type = obj.TYPE_CONST
						n++
					}
				}
				continue
			case _Write:
				if p.As != pp.As || p.From.Type != pp.From.Type {
					break
				}
				if p.From.Type == obj.TYPE_CONST && p.From.Offset == pp.From.Offset {
					excise(rr)
					n++
					continue
				} else if p.From.Type == obj.TYPE_FCONST {
					if p.From.Val.(float64) == pp.From.Val.(float64) {
						excise(rr)
						n++
						continue
					}
				}
			}
			break
		}
	}
	return n
}
コード例 #22
0
ファイル: peep.go プロジェクト: glycerine/zygomys
// copy1 replaces uses of v2 with v1 starting at r and returns true if
// all uses were rewritten.
func copy1(v1 *obj.Addr, v2 *obj.Addr, r *gc.Flow, f bool) 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=%v\n", gc.Ctxt.Dconv(v2), gc.Ctxt.Dconv(v1), f)
	}
	for ; r != nil; r = r.S1 {
		p := r.Prog
		if gc.Debug['P'] != 0 {
			fmt.Printf("%v", p)
		}
		if !f && gc.Uniqp(r) == nil {
			// Multiple predecessors; conservatively
			// assume v1 was set on other path
			f = true

			if gc.Debug['P'] != 0 {
				fmt.Printf("; merge; f=%v", f)
			}
		}

		switch t := copyu(p, v2, nil); 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 {
				if gc.Debug['P'] == 0 {
					return false
				}
				if t == 4 {
					fmt.Printf("; %v used+set and f=%v; return 0\n", gc.Ctxt.Dconv(v2), f)
				} else {
					fmt.Printf("; %v used and f=%v; 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 {
			t := copyu(p, v1, nil)
			if t == 2 || t == 3 || t == 4 {
				f = true
				if gc.Debug['P'] != 0 {
					fmt.Printf("; %v set and !f; f=%v", 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
}
コード例 #23
0
ファイル: peep.go プロジェクト: glycerine/zygomys
/*
 * 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 {
	p := r0.Prog
	v1 := &p.From
	if !regtyp(v1) {
		return false
	}
	v2 := &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
		}

		// TODO(rsc): Whatever invalidated the info should have done this call.
		proginfo(p)

		if (p.Info.Flags&gc.CanRegRead != 0) && p.To.Type == obj.TYPE_REG {
			p.Info.Flags |= gc.RegRead
			p.Info.Flags &^= (gc.CanRegRead | gc.RightRead)
			p.Reg = p.To.Reg
		}

		switch p.As {
		case arm.AMULLU,
			arm.AMULA,
			arm.AMVN:
			return false
		}

		if p.Info.Flags&(gc.RightRead|gc.RightWrite) == gc.RightWrite {
			if p.To.Type == v1.Type {
				if p.To.Reg == v1.Reg {
					if p.Scond == arm.C_SCOND_NONE {
						copysub(&p.To, v1, v2, true)
						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, true)
							copysub1(p, v1, v2, true)
							copysub(&p.To, v1, v2, true)
							if gc.Debug['P'] != 0 {
								fmt.Printf("%v\n", r.Prog)
							}
						}

						v1.Reg, v2.Reg = v2.Reg, v1.Reg
						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, false) || copysub1(p, v1, v2, false) || copysub(&p.To, v1, v2, false) {
			break
		}
	}

	return false
}