matching the new flags. To disallow flags that would otherwise be allowed,
set CGO_CFLAGS_DISALLOW to a regular expression matching arguments
that must be disallowed. In both cases the regular expression must match
a full argument: to allow -mfoo=bar, use CGO_CFLAGS_ALLOW='-mfoo.*',
not just CGO_CFLAGS_ALLOW='-mfoo'. Similarly named variables control
the allowed CPPFLAGS, CXXFLAGS, FFLAGS, and LDFLAGS.

"Switch" statements provide multi-way execution.
An expression or type is compared to the "cases"
inside the "switch" to determine which branch
to execute.
</p>

<pre class="ebnf">
SwitchStmt = ExprSwitchStmt | TypeSwitchStmt .
</pre>

<p>
There are two forms: expression switches and type switches.
In an expression switch, the cases contain expressions that are compared
against the value of the switch expression.

//
// RET
//
//	LRETRN	comma // asm doesn't support the trailing comma.
//	{
//		outcode(int($1), &nullgen, 0, &nullgen);
//	}
	SYSCALL
	BEQ	R1, 2(PC)
	RET


// More JMP/JAL cases, and canonical names JMP, CALL.

	JAL	foo(SB) // CALL foo(SB)
	BEQ	R1, 2(PC)
	JMP	foo(SB)
	CALL	foo(SB)
	RET	foo(SB)

	// unary operation
	NEGW	R1, R2 // 00011023
	NEGV	R1, R2 // 0001102f

	VGATHERQPD 640(R15)(Z20*2), K6, Z10 // 6252fd4693546750
	VGATHERQPD 960(R15)(Z10*2), K6, Z20 // 6282fd4e93645778
	VGATHERQPD 1280(R15)(Z0*2), K6, Z10 // 6252fd4e93944700050000
	// EVEX: corner cases for High-16 registers.
	VADDPD X31, X16, X15          // 6211fd0058ff
	VADDPD X23, X15, X16          // 62a1850858c7
	VADDPD Y31, Y16, Y15          // 6211fd2058ff
	VADDPD Y23, Y15, Y16          // 62a1852858c7

//
// In most cases, new([Buffer]) (or just declaring a [Buffer] variable) is
// sufficient to initialize a [Buffer].
func NewBuffer(buf []byte) *Buffer { return &Buffer{buf: buf} }

// NewBufferString creates and initializes a new [Buffer] using string s as its
// initial contents. It is intended to prepare a buffer to read an existing
// string.
//

		output string // Expected value of string read
	}
	vectors := []struct {
		file  string
		cases []testCase
	}{{
		file: "testdata/gnu.tar",
		cases: []testCase{
			{4, "Kilt"},
			{6, "Google"},
		},
	}, {
		file: "testdata/sparse-formats.tar",
		cases: []testCase{
			{2, "\x00G"},
			{4, "\x00G\x00o"},
			{6, "\x00G\x00o\x00G"},
			{8, "\x00G\x00o\x00G\x00o"},

		if err := w.Close(); test.ok == (err != nil) {
			t.Fatal(err)
		}

		if w.closed != test.ok {
			t.Fatalf("Writer.closed: got %v, want %v", w.closed, test.ok)
		}

		// skip read test in failure cases
		if !test.ok {
			continue
		}

		// read it back
		r, err := NewReader(bytes.NewReader(buf.Bytes()), int64(buf.Len()))
		if err != nil {
			t.Fatal(err)
		}
		if r.Comment != test.comment {

// Copyright 2017 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

// The cases are auto-generated by disassembler.
// The uncommented cases means they can be handled by assembler
// and they are consistent with disassembler decoding.
// TODO means they cannot be handled by current assembler.

#include "../../../../../runtime/textflag.h"

// AST expression onto a single line. The lexer normally inserts a
// semicolon at each newline, so we can replace newline with semicolon.
// However, we can't do that in cases where the lexer would not insert
// a semicolon. We only have to worry about cases that can occur in an
// expression passed through gofmt, which means composite literals and
// (due to the printer possibly inserting newlines because of position

	// When the function argument is a conversion to unsafe.Pointer,
	// we unwrap the conversion before checking the pointer,
	// and then wrap again when calling C.f. This lets us check
	// the real type of the pointer in some cases. See issue #25941.
	//
	// When the call to C.f is deferred, we use an additional function
	// literal to evaluate the arguments at the right time.
	//    defer func() func() {
	//            _cgo0 := p