output.txt

C:\temp>cl /O2 /nologo /FAs test.cpp
test.cpp

C:\temp>test
0000000000000001
0000000100000000

test.asm

; Listing generated by Microsoft (R) Optimizing Compiler Version 16.00.40219.01 

  TITLE	C:\temp\test.cpp
	.686P
	.XMM
	include listing.inc
	.model	flat

INCLUDELIB LIBCMT
INCLUDELIB OLDNAMES

PUBLIC	?f@@YA_KH@Z					; f
; Function compile flags: /Ogtpy
; File c:\temp\test.cpp
;	COMDAT ?f@@YA_KH@Z
_TEXT	SEGMENT
_n$ = 8							; size = 4
?f@@YA_KH@Z PROC					; f, COMDAT

; 8    :   return __ll_lshift(1ull, n);

	mov	ecx, DWORD PTR _n$[esp-4]
	mov	eax, 1
	xor	edx, edx
	shld	edx, eax, ecx
	shl	eax, ecx

; 9    : }

	ret	0
?f@@YA_KH@Z ENDP					; f
_TEXT	ENDS
PUBLIC	?g@@YA_KH@Z					; g
EXTRN	__allshl:PROC
; Function compile flags: /Ogtpy
;	COMDAT ?g@@YA_KH@Z
_TEXT	SEGMENT
_n$ = 8							; size = 4
?g@@YA_KH@Z PROC					; g, COMDAT

; 13   :   return 1ull << n;

	mov	ecx, DWORD PTR _n$[esp-4]
	mov	eax, 1
	xor	edx, edx
	jmp	__allshl
?g@@YA_KH@Z ENDP					; g
_TEXT	ENDS
PUBLIC	??_C@_09MAJGPEFC@?$CF016I64x?6?$AA@		; `string'
PUBLIC	_main
EXTRN	_printf:PROC
;	COMDAT ??_C@_09MAJGPEFC@?$CF016I64x?6?$AA@
CONST	SEGMENT
??_C@_09MAJGPEFC@?$CF016I64x?6?$AA@ DB '%016I64x', 0aH, 00H ; `string'
; Function compile flags: /Ogtpy
CONST	ENDS
;	COMDAT _main
_TEXT	SEGMENT
_main	PROC						; COMDAT

; 18   :   printf("%016I64x\n", f(32));

	xor	ecx, ecx
	mov	eax, 1
	shld	ecx, eax, 32
	push	ecx
	shl	eax, 32					; 00000020H
	push	eax
	push	OFFSET ??_C@_09MAJGPEFC@?$CF016I64x?6?$AA@
	call	_printf

; 19   :   printf("%016I64x\n", g(32));

	push	1
	push	0
	push	OFFSET ??_C@_09MAJGPEFC@?$CF016I64x?6?$AA@
	call	_printf
	add	esp, 24					; 00000018H

; 20   :   return 0;

	xor	eax, eax

; 21   : }

	ret	0
_main	ENDP
_TEXT	ENDS
END

test.cpp

#include <stdio.h>
#include <intrin.h>

#pragma intrinsic(__ll_lshift)

unsigned long long f(int n)
{
  return __ll_lshift(1ull, n);
}

unsigned long long g(int n)
{
  return 1ull << n;
}

int main()
{
  printf("%016I64x\n", f(32));
  printf("%016I64x\n", g(32));
  return 0;
}