c/2583: A function declared __inline__ takes exponential compile time on IA64

mark.dewing@intel.com mark.dewing@intel.com
Wed Apr 18 15:16:00 GMT 2001


>Number:         2583
>Category:       c
>Synopsis:       A function declared __inline__ takes exponential compile time on IA64
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Apr 18 15:16:00 PDT 2001
>Closed-Date:
>Last-Modified:
>Originator:     Mark Dewing
>Release:        gcc version 3.0 20010402
>Organization:
>Environment:
IA64 Linux 2.4.0test10-001115-58smp
>Description:
A function with some integer arithmetic operations is declared with the __inline__ specifier. With -O or higher, it takes a long time to compile on IA64. In particular, it is exponential in the number of statements
(count *= 10;) in the function.
The x86 gcc (same 200010402 snapshot) does not have this behavior.

>How-To-Repeat:
// compile with -O or higher
int count = 1; // no problem with double
static __inline__ void
 toobig(void ) {

    count *= 10; // also depends on this value
    count *= 10; // takes more time for larger values
// 2
    count *= 10;
    count *= 10;
// 4  
    count *= 10;
    count *= 10;
// 6
    count *= 10;
    count *= 10;
// 8  
    count *= 10;
    count *= 10;
// 10
    count *= 10;
    count *= 10;
// 12  
    count *= 10;
    count *= 10;
// 14
    count *= 10;
    count *= 10;
// 16  
    count *= 10;
// 17 
    count *= 10;
// 18  
    count *= 10;
// 19
    count *= 10;
// 20
    count *= 10;
// 21
#if 0
    count *= 2;
// 22
    count *= 10;
// 23  
    count *= 10;
// 24
#endif

} 

int main(){
 toobig();
 printf("count = %d\n",count);
}
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted:



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