match := ir.NewBinaryExpr(base.Pos, eq, itabType(tab), rtyp)
			eqtype = ir.NewLogicalExpr(base.Pos, andor, nonnil, match)
		}
		// Check for data equal.
		eqdata := ir.NewBinaryExpr(base.Pos, eq, ifaceData(n.Pos(), l, r.Type()), r)
		// Put it all together.
		expr := ir.NewLogicalExpr(base.Pos, andor, eqtype, eqdata)
		return finishCompare(n, expr, init)
	}

			isNil := ir.NewBinaryExpr(base.Pos, ir.OEQ, unsafePtr, typecheck.NodNil())
			gtZero := ir.NewBinaryExpr(base.Pos, ir.OGT, typecheck.Conv(len, lenType), ir.NewInt(base.Pos, 0))
			nifPtr.Cond =
				ir.NewLogicalExpr(base.Pos, ir.OANDAND, isNil, gtZero)
			nifPtr.Body.Append(mkcall("panicunsafeslicenilptr", nil, &nifPtr.Body))
			appendWalkStmt(init, nifPtr)

			h := ir.NewSliceHeaderExpr(n.Pos(), sliceType,

func (c *exprClause) test(exprname ir.Node) ir.Node {
	// Integer range.
	if c.hi != c.lo {
		low := ir.NewBinaryExpr(c.pos, ir.OGE, exprname, c.lo)
		high := ir.NewBinaryExpr(c.pos, ir.OLE, exprname, c.hi)
		return ir.NewLogicalExpr(c.pos, ir.OANDAND, low, high)
	}

	// Optimize "switch true { ...}" and "switch false { ... }".
	if ir.IsConst(exprname, constant.Bool) && !c.lo.Type().IsInterface() {
		if ir.BoolVal(exprname) {
			return c.lo