performance - Checking perfomance between if(false){}else{if(false){}} and if(false){}else if(false){} -


please checking performance between 2 block code bellow. can't think both same when run-time(overlook figure element , same condition).

 // block     if(condition1)     {        //     }     else     {    if(condition2)         {            //         }         else         {    if(condition3)             {                //             }             else             {    if(condition4)                 {                    //                 }             }         }     }      //--------------------------------     // block ii     if(condition1)     {        //     }     else  if(condition2)     {        //     }     else  if(condition3)     {        //     }     else  if(condition4)     {        //     }

help me!

assuming language c (you didn't specify), can verify 2 snippets generate exactly same code comparing assembly output of gcc:

#!/bin/bash diff <(gcc -o0 -s -o - -x c - <<eof extern int condition1(); extern int condition2(); extern int condition3(); extern int condition4(); extern void do_something1(); extern void do_something2(); extern void do_something3(); extern void do_something4();  void main() {     if(condition1())     {        do_something1();     }     else     {    if(condition2())         {            do_something2();         }         else         {    if(condition3())             {                do_something3();             }             else             {    if(condition4())                 {                    do_something4();                 }             }         }     } } eof ) <( gcc -o0 -s -o - -x c - <<eof extern int condition1(); extern int condition2(); extern int condition3(); extern int condition4(); extern void do_something1(); extern void do_something2(); extern void do_something3(); extern void do_something4();  void main() {     if(condition1())     {        do_something1();     }     else if(condition2())     {        do_something2();     }     else if(condition3())     {        do_something3();     }     else if(condition4())     {        do_something4();     } } eof )

this generates no output (you can prove test valid (e.g.) removing last condition 1 of functions , observing shows difference).

since assembly language output identical 2 blocks, can deduce performance characteristics must same.


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