1.cc

#include <stdio.h>
#include <vector>

std::vector<int> vec();

int main() {
  auto l = vec();
  for (auto i = 0ul; i < l.size(); i++) {
    puts("ok.")
  }
  return 0;
}

clang++, O2

	.text
	.file	"1.cc"
	.globl	main
	.align	16, 0x90
	.type	main,@function
main:                                   # @main
	.cfi_startproc
# BB#0:
	pushq	%rbx
.Ltmp0:
	.cfi_def_cfa_offset 16
	subq	$32, %rsp
.Ltmp1:
	.cfi_def_cfa_offset 48
.Ltmp2:
	.cfi_offset %rbx, -16
	leaq	8(%rsp), %rdi
	callq	_Z3vecv
	movq	8(%rsp), %rdi
	xorl	%ebx, %ebx
	cmpq	%rdi, 16(%rsp)
	je	.LBB0_1
	.align	16, 0x90
.LBB0_4:                                # %.lr.ph
                                        # =>This Inner Loop Header: Depth=1
	movl	$.L.str, %edi
	callq	puts
	incq	%rbx
	movq	8(%rsp), %rdi
	movq	16(%rsp), %rax
	subq	%rdi, %rax
	sarq	$2, %rax
	cmpq	%rax, %rbx
	jb	.LBB0_4
.LBB0_1:                                # %._crit_edge
	testq	%rdi, %rdi
	je	.LBB0_3
# BB#2:
	callq	_ZdlPv
.LBB0_3:                                # %_ZNSt6vectorIiSaIiEED2Ev.exit
	xorl	%eax, %eax
	addq	$32, %rsp
	popq	%rbx
	retq
.Lfunc_end0:
	.size	main, .Lfunc_end0-main
	.cfi_endproc

	.type	.L.str,@object          # @.str
	.section	.rodata.str1.1,"aMS",@progbits,1
.L.str:
	.asciz	"ok."
	.size	.L.str, 4


	.ident	"clang version 3.7.0 (tags/RELEASE_370/final 251906)"
	.section	".note.GNU-stack","",@progbits

g++, O2

	.file	"1.cc"
	.section	.rodata.str1.1,"aMS",@progbits,1
.LC0:
	.string	"ok."
	.section	.text.startup,"ax",@progbits
	.p2align 4,,15
	.globl	main
	.type	main, @function
main:
.LFB705:
	.cfi_startproc
	.cfi_personality 0x3,__gxx_personality_v0
	.cfi_lsda 0x3,.LLSDA705
	pushq	%rbx
	.cfi_def_cfa_offset 16
	.cfi_offset 3, -16
	subq	$32, %rsp
	.cfi_def_cfa_offset 48
	movq	%rsp, %rdi
.LEHB0:
	call	_Z3vecv
.LEHE0:
	movq	(%rsp), %rdi
	movq	8(%rsp), %rax
	subq	%rdi, %rax
	sarq	$2, %rax
	testq	%rax, %rax
	je	.L2
	xorl	%ebx, %ebx
	.p2align 4,,10
	.p2align 3
.L3:
	movl	$.LC0, %edi
.LEHB1:
	call	puts
.LEHE1:
	movq	(%rsp), %rdi
	movq	8(%rsp), %rax
	addq	$1, %rbx
	subq	%rdi, %rax
	sarq	$2, %rax
	cmpq	%rax, %rbx
	jb	.L3
.L2:
	testq	%rdi, %rdi
	je	.L11
	call	_ZdlPv
.L11:
	addq	$32, %rsp
	.cfi_remember_state
	.cfi_def_cfa_offset 16
	xorl	%eax, %eax
	popq	%rbx
	.cfi_def_cfa_offset 8
	ret
.L7:
	.cfi_restore_state
	movq	(%rsp), %rdi
	movq	%rax, %rbx
	testq	%rdi, %rdi
	je	.L6
	call	_ZdlPv
.L6:
	movq	%rbx, %rdi
.LEHB2:
	call	_Unwind_Resume
.LEHE2:
	.cfi_endproc
.LFE705:
	.globl	__gxx_personality_v0
	.section	.gcc_except_table,"a",@progbits
.LLSDA705:
	.byte	0xff
	.byte	0xff
	.byte	0x1
	.uleb128 .LLSDACSE705-.LLSDACSB705
.LLSDACSB705:
	.uleb128 .LEHB0-.LFB705
	.uleb128 .LEHE0-.LEHB0
	.uleb128 0
	.uleb128 0
	.uleb128 .LEHB1-.LFB705
	.uleb128 .LEHE1-.LEHB1
	.uleb128 .L7-.LFB705
	.uleb128 0
	.uleb128 .LEHB2-.LFB705
	.uleb128 .LEHE2-.LEHB2
	.uleb128 0
	.uleb128 0
.LLSDACSE705:
	.section	.text.startup
	.size	main, .-main
	.ident	"GCC: (Ubuntu 4.8.4-2ubuntu1~14.04) 4.8.4"
	.section	.note.GNU-stack,"",@progbits