[Bug c/44947] Optimizer doesn't see setjmp()

[cm1 at mumac dot de]

--- Comment #4 from cm1 at mumac dot de  2010-07-15 10:14 ---
Thanks for the quick explanation and sorry for joining the club of "submit
first, read the specs later" folks -- I actually thought I knew them ;)

It makes of course sense to use volatile in the presence of setjmp/longjmp but
in our case this is hidden underneath a try/catch framework with tons of code
being unaware of setjmp/longjmp being involved. Either way, that's our problem.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44947

[Bug c/44947] Optimizer doesn't see setjmp()

[pinskia at gmail dot com]

--- Comment #3 from pinskia at gmail dot com  2010-07-15 09:19 ---
Subject: Re:  Optimizer doesn't see setjmp()



On Jul 15, 2010, at 2:15 AM, "cm1 at mumac dot de"  wrote:

>
>
> --- Comment #1 from cm1 at mumac dot de  2010-07-15 09:15 ---
> Sorry, I edited the contents of the precompiler output to make it  
> more readable
> and messed up the auto variable name. Please use this code:
>
> #include 
> #include 
> #include 
>
> #define EXC_TRY   1
> #define EXC_CATCH 2
>
> func()
> {
>  const char *p = NULL;/*** auto variable  
> ***/


IRRC you need volatile here as defined by the c standard.


>  {
>jmp_buf exc_jmp_buf;
>int exc_state;
>
>if (setjmp(exc_jmp_buf) == 0) {/*** setjmp() ***/
>  exc_state = EXC_TRY;
>} else {
>  exc_state = EXC_CATCH;
>}
>
>if (exc_state == EXC_TRY) {/*** TRY BLOCK ***/
>  p = "some value";
>}
>
>if (exc_state == EXC_CATCH) {  /*** CATCH BLOCK  
> ***/
>  puts(p);
>}
>  }
> }
>
>
> -- 
>
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44947
>


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44947

Re: [Bug c/44947] Optimizer doesn't see setjmp()

[Andrew Pinski]

On Jul 15, 2010, at 2:15 AM, "cm1 at mumac dot de" > wrote:





--- Comment #1 from cm1 at mumac dot de  2010-07-15 09:15 ---
Sorry, I edited the contents of the precompiler output to make it  
more readable

and messed up the auto variable name. Please use this code:

#include 
#include 
#include 

#define EXC_TRY   1
#define EXC_CATCH 2

func()
{
 const char *p = NULL;/*** auto variable  
***/



IRRC you need volatile here as defined by the c standard.



 {
   jmp_buf exc_jmp_buf;
   int exc_state;

   if (setjmp(exc_jmp_buf) == 0) {/*** setjmp() ***/
 exc_state = EXC_TRY;
   } else {
 exc_state = EXC_CATCH;
   }

   if (exc_state == EXC_TRY) {/*** TRY BLOCK ***/
 p = "some value";
   }

   if (exc_state == EXC_CATCH) {  /*** CATCH BLOCK  
***/

 puts(p);
   }
 }
}


--


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44947

[Bug c/44947] Optimizer doesn't see setjmp()

[rguenth at gcc dot gnu dot org]

--- Comment #2 from rguenth at gcc dot gnu dot org  2010-07-15 09:18 ---
You need to mark auto variables that are life across setjmp/longjmp calls as
volatile.


-- 

rguenth at gcc dot gnu dot org changed:

   What|Removed |Added

 Status|UNCONFIRMED |RESOLVED
 Resolution||INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44947

[Bug c/44947] Optimizer doesn't see setjmp()

[cm1 at mumac dot de]

--- Comment #1 from cm1 at mumac dot de  2010-07-15 09:15 ---
Sorry, I edited the contents of the precompiler output to make it more readable
and messed up the auto variable name. Please use this code:

#include 
#include 
#include 

#define EXC_TRY   1
#define EXC_CATCH 2

func()
{
  const char *p = NULL;/*** auto variable ***/
  {
jmp_buf exc_jmp_buf;
int exc_state;

if (setjmp(exc_jmp_buf) == 0) {/*** setjmp() ***/
  exc_state = EXC_TRY;
} else {
  exc_state = EXC_CATCH;
}

if (exc_state == EXC_TRY) {/*** TRY BLOCK ***/
  p = "some value";
}

if (exc_state == EXC_CATCH) {  /*** CATCH BLOCK ***/
  puts(p);
}
  }
}


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44947