C source
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static inline int32_t cround64(double val)
{
    val += 6755399441055744.0;
    return *(int32_t*)&val;
}


gcc 10.1
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cround64:                                                                       
        sub esp, 12                                                             
        fld dword [magic]                                                       
        fadd qword [esp + 16]                                                   
        fstp qword [esp]                                                        
        mov eax, [esp]                                                          
        add esp, 12                                                             
        ret                                                                     
magic   dd 1505755136


gcc 4.1
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cround64:
	push ebp
	mov ebp, esp
	sub esp, 8
	mov eax, [ebp - 8]
	leave
	ret