unsafe /* ERROR "not used" */ .Alignof(x)

	var y S0
	assert(unsafe.Alignof(y.a) == 1)
	assert(unsafe.Alignof(y.b) == 4)
	assert(unsafe.Alignof(y.c) == 8)
	assert(unsafe.Alignof(y.d) == 1)
	assert(unsafe.Alignof(y.e) == 8)

	var s []byte
	_ = unsafe.Alignof(s)
	_ = unsafe.Alignof(s... /* ERROR "invalid use of ..." */ )
}

func Alignof2() {
	f1 := func() (x int32) { return }

// of a field of that type within a struct. This case is the same as the
// value returned by [reflect.TypeOf](s.f).FieldAlign().
// The return value of Alignof is a Go constant if the type of the argument
// does not have variable size.
// (See the description of [Sizeof] for a definition of variable sized types.)
func Alignof(x ArbitraryType) uintptr

		}

		x.mode = value
		x.typ = Typ[UnsafePointer]
		if check.recordTypes() {
			check.recordBuiltinType(call.Fun, makeSig(x.typ, x.typ, y.typ))
		}

	case _Alignof:
		// unsafe.Alignof(x T) uintptr
		check.assignment(x, nil, "argument to unsafe.Alignof")
		if x.mode == invalid {
			return
		}

		if hasVarSize(x.typ, nil) {
			x.mode = value
			if check.recordTypes() {

		}

		x.mode = value
		x.typ = Typ[UnsafePointer]
		if check.recordTypes() {
			check.recordBuiltinType(call.Fun, makeSig(x.typ, x.typ, y.typ))
		}

	case _Alignof:
		// unsafe.Alignof(x T) uintptr
		check.assignment(x, nil, "argument to unsafe.Alignof")
		if x.mode == invalid {
			return
		}

		if hasVarSize(x.typ, nil) {
			x.mode = value
			if check.recordTypes() {

	case *ast.Ident:
		id = fun
	case *ast.SelectorExpr:
		id = fun.Sel
	}
	if fun, ok := pass.TypesInfo.Uses[id].(*types.Builtin); ok {
		switch fun.Name() {
		case "new", "len", "cap", "Sizeof", "Offsetof", "Alignof":
			return
		}
	}
	for _, x := range ce.Args {
		if path := lockPathRhs(pass, x); path != nil {
			pass.ReportRangef(x, "call of %s copies lock value: %v", analysisutil.Format(pass.Fset, ce.Fun), path)
		}

<li>For a variable <code>x</code> of any type: <code>unsafe.Alignof(x)</code> is at least 1.
</li>

<li>For a variable <code>x</code> of struct type: <code>unsafe.Alignof(x)</code> is the largest of
   all the values <code>unsafe.Alignof(x.f)</code> for each field <code>f</code> of <code>x</code>, but at least 1.
</li>

<li>For a variable <code>x</code> of array type: <code>unsafe.Alignof(x)</code> is the same as

	"aN": {"&=", 2, precAssign},
	"aS": {"=", 2, precAssign},
	"aa": {"&&", 2, precLogicalAnd},
	"ad": {"&", 1, precUnary},
	"an": {"&", 2, precAnd},
	"at": {"alignof ", 1, precUnary},
	"aw": {"co_await ", 1, precPrimary},
	"az": {"alignof ", 1, precUnary},
	"cc": {"const_cast", 2, precPostfix},
	"cl": {"()", 2, precPostfix},
	// cp is not in the ABI but is used by clang "when the call

		// caller reserved spill space.
		p.dstSpill = alignUp(p.dstSpill, uintptr(t.Align_))
		p.dstSpill += t.Size_
	} else {
		// Register assignment failed.
		// Undo the work and stack assign.
		p.parts = oldParts

		// The Go ABI aligns arguments.
		p.dstStackSize = alignUp(p.dstStackSize, uintptr(t.Align_))

		// Copy just the size of the argument. Note that this

	// nil pointer is always suitably aligned (#47430).
	if p == nil {
		return
	}

	// Check that (*[n]elem)(p) is appropriately aligned.
	// Note that we allow unaligned pointers if the types they point to contain
	// no pointers themselves. See issue 37298.
	// TODO(mdempsky): What about fieldAlign?
	if elem.Pointers() && uintptr(p)&(uintptr(elem.Align_)-1) != 0 {
		throw("checkptr: misaligned pointer conversion")

For 386 and amd64, the compiler will use information from PGO to align certain
hot blocks in loops.  This improves performance an additional 1-1.5% at
a cost of an additional 0.1% text and binary size.  This is currently only implemented
on 386 and amd64 because it has not shown an improvement on other platforms.
Hot block alignment can be disabled with `-gcflags=[<packages>=]-d=alignhot=0`

## Assembler {#assembler}

## Linker {#linker}