Beispiel #1
0
func ginscmp(op gc.Op, t *gc.Type, n1, n2 *gc.Node, likely int) *obj.Prog {
	if t.IsInteger() && n1.Op == gc.OLITERAL && n1.Int64() == 0 && n2.Op != gc.OLITERAL {
		op = gc.Brrev(op)
		n1, n2 = n2, n1
	}
	var r1, r2, g1, g2 gc.Node
	gc.Regalloc(&r1, t, n1)
	gc.Regalloc(&g1, n1.Type, &r1)
	gc.Cgen(n1, &g1)
	gmove(&g1, &r1)
	if t.IsInteger() && n2.Op == gc.OLITERAL && n2.Int64() == 0 {
		gins(arm.ACMP, &r1, n2)
	} else {
		gc.Regalloc(&r2, t, n2)
		gc.Regalloc(&g2, n1.Type, &r2)
		gc.Cgen(n2, &g2)
		gmove(&g2, &r2)
		gins(optoas(gc.OCMP, t), &r1, &r2)
		gc.Regfree(&g2)
		gc.Regfree(&r2)
	}
	gc.Regfree(&g1)
	gc.Regfree(&r1)
	return gc.Gbranch(optoas(op, t), nil, likely)
}
Beispiel #2
0
func ginscmp(op gc.Op, t *gc.Type, n1, n2 *gc.Node, likely int) *obj.Prog {
	if t.IsInteger() && n1.Op == gc.OLITERAL && n2.Op != gc.OLITERAL {
		// Reverse comparison to place constant last.
		op = gc.Brrev(op)
		n1, n2 = n2, n1
	}

	var r1, r2, g1, g2 gc.Node
	gc.Regalloc(&r1, t, n1)
	gc.Regalloc(&g1, n1.Type, &r1)
	gc.Cgen(n1, &g1)
	gmove(&g1, &r1)
	if t.IsInteger() && gc.Isconst(n2, gc.CTINT) {
		ginscon2(optoas(gc.OCMP, t), &r1, n2.Int64())
	} else {
		gc.Regalloc(&r2, t, n2)
		gc.Regalloc(&g2, n1.Type, &r2)
		gc.Cgen(n2, &g2)
		gmove(&g2, &r2)
		gcmp(optoas(gc.OCMP, t), &r1, &r2)
		gc.Regfree(&g2)
		gc.Regfree(&r2)
	}
	gc.Regfree(&g1)
	gc.Regfree(&r1)
	return gc.Gbranch(optoas(op, t), nil, likely)
}
Beispiel #3
0
func ginscmp(op gc.Op, t *gc.Type, n1, n2 *gc.Node, likely int) *obj.Prog {
	if t.IsInteger() || t.Etype == gc.Tptr {
		if (n1.Op == gc.OLITERAL || n1.Op == gc.OADDR && n1.Left.Op == gc.ONAME) && n2.Op != gc.OLITERAL {
			// Reverse comparison to place constant (including address constant) last.
			op = gc.Brrev(op)
			n1, n2 = n2, n1
		}
	}

	// General case.
	var r1, r2, g1, g2 gc.Node

	// A special case to make write barriers more efficient.
	// Comparing the first field of a named struct can be done directly.
	base := n1
	if n1.Op == gc.ODOT && n1.Left.Type.IsStruct() && n1.Left.Type.Field(0).Sym == n1.Sym {
		base = n1.Left
	}

	if base.Op == gc.ONAME && base.Class != gc.PAUTOHEAP || n1.Op == gc.OINDREG {
		r1 = *n1
	} else {
		gc.Regalloc(&r1, t, n1)
		gc.Regalloc(&g1, n1.Type, &r1)
		gc.Cgen(n1, &g1)
		gmove(&g1, &r1)
	}
	if n2.Op == gc.OLITERAL && t.IsInteger() || n2.Op == gc.OADDR && n2.Left.Op == gc.ONAME && n2.Left.Class == gc.PEXTERN {
		r2 = *n2
	} else {
		gc.Regalloc(&r2, t, n2)
		gc.Regalloc(&g2, n1.Type, &r2)
		gc.Cgen(n2, &g2)
		gmove(&g2, &r2)
	}
	gins(optoas(gc.OCMP, t), &r1, &r2)
	if r1.Op == gc.OREGISTER {
		gc.Regfree(&g1)
		gc.Regfree(&r1)
	}
	if r2.Op == gc.OREGISTER {
		gc.Regfree(&g2)
		gc.Regfree(&r2)
	}
	return gc.Gbranch(optoas(op, t), nil, likely)
}
Beispiel #4
0
func bgen_float(n *gc.Node, wantTrue bool, likely int, to *obj.Prog) {
	nl := n.Left
	nr := n.Right
	op := n.Op
	if !wantTrue {
		// brcom is not valid on floats when NaN is involved.
		p1 := gc.Gbranch(obj.AJMP, nil, 0)
		p2 := gc.Gbranch(obj.AJMP, nil, 0)
		gc.Patch(p1, gc.Pc)

		// No need to avoid re-genning ninit.
		bgen_float(n, true, -likely, p2)

		gc.Patch(gc.Gbranch(obj.AJMP, nil, 0), to)
		gc.Patch(p2, gc.Pc)
		return
	}

	if gc.Thearch.Use387 {
		op = gc.Brrev(op) // because the args are stacked
		if op == gc.OGE || op == gc.OGT {
			// only < and <= work right with NaN; reverse if needed
			nl, nr = nr, nl
			op = gc.Brrev(op)
		}

		var ax, n2, tmp gc.Node
		gc.Nodreg(&tmp, nr.Type, x86.REG_F0)
		gc.Nodreg(&n2, nr.Type, x86.REG_F0+1)
		gc.Nodreg(&ax, gc.Types[gc.TUINT16], x86.REG_AX)
		if gc.Simsimtype(nr.Type) == gc.TFLOAT64 {
			if nl.Ullman > nr.Ullman {
				gc.Cgen(nl, &tmp)
				gc.Cgen(nr, &tmp)
				gins(x86.AFXCHD, &tmp, &n2)
			} else {
				gc.Cgen(nr, &tmp)
				gc.Cgen(nl, &tmp)
			}
			gins(x86.AFUCOMPP, &tmp, &n2)
		} else {
			// TODO(rsc): The moves back and forth to memory
			// here are for truncating the value to 32 bits.
			// This handles 32-bit comparison but presumably
			// all the other ops have the same problem.
			// We need to figure out what the right general
			// solution is, besides telling people to use float64.
			var t1 gc.Node
			gc.Tempname(&t1, gc.Types[gc.TFLOAT32])

			var t2 gc.Node
			gc.Tempname(&t2, gc.Types[gc.TFLOAT32])
			gc.Cgen(nr, &t1)
			gc.Cgen(nl, &t2)
			gmove(&t2, &tmp)
			gins(x86.AFCOMFP, &t1, &tmp)
		}
		gins(x86.AFSTSW, nil, &ax)
		gins(x86.ASAHF, nil, nil)
	} else {
		// Not 387
		if !nl.Addable {
			nl = gc.CgenTemp(nl)
		}
		if !nr.Addable {
			nr = gc.CgenTemp(nr)
		}

		var n2 gc.Node
		gc.Regalloc(&n2, nr.Type, nil)
		gmove(nr, &n2)
		nr = &n2

		if nl.Op != gc.OREGISTER {
			var n3 gc.Node
			gc.Regalloc(&n3, nl.Type, nil)
			gmove(nl, &n3)
			nl = &n3
		}

		if op == gc.OGE || op == gc.OGT {
			// only < and <= work right with NopN; reverse if needed
			nl, nr = nr, nl
			op = gc.Brrev(op)
		}

		gins(foptoas(gc.OCMP, nr.Type, 0), nl, nr)
		if nl.Op == gc.OREGISTER {
			gc.Regfree(nl)
		}
		gc.Regfree(nr)
	}

	switch op {
	case gc.OEQ:
		// neither NE nor P
		p1 := gc.Gbranch(x86.AJNE, nil, -likely)
		p2 := gc.Gbranch(x86.AJPS, nil, -likely)
		gc.Patch(gc.Gbranch(obj.AJMP, nil, 0), to)
		gc.Patch(p1, gc.Pc)
		gc.Patch(p2, gc.Pc)
	case gc.ONE:
		// either NE or P
		gc.Patch(gc.Gbranch(x86.AJNE, nil, likely), to)
		gc.Patch(gc.Gbranch(x86.AJPS, nil, likely), to)
	default:
		gc.Patch(gc.Gbranch(optoas(op, nr.Type), nil, likely), to)
	}
}