[Bug c/54743] New: Large loop runs endingless

[slbyan at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54743



 Bug #: 54743

   Summary: Large loop runs endingless

Classification: Unclassified

   Product: gcc

   Version: 4.6.3

Status: UNCONFIRMED

  Severity: normal

  Priority: P3

 Component: c

AssignedTo: unassig...@gcc.gnu.org

ReportedBy: slb...@gmail.com





When the loops is 10, the -O3 or -O2 -funroll-loops make the code runs

fast enough(~17sec, on Intel(R) Core(TM)2 Duo CPU E7400 @ 2.80GHz), and when

double the loops (20), the time doubles as expected. However, when

loops is 30, the code runs hours without ending.

The code is:



#include 

static long double vec_a[16] ={

1.0,2.0,3.0,4.0,

11.0,22.0,33.0,44.0,

111.0,222.0,333.0,444.0,

.0,.0,.0,.0};

static long double vec_b[16] ={

1.0,2.0,3.0,4.0,

11.0,22.0,33.0,44.0,

111.0,222.0,333.0,444.0,

.0,.0,.0,.0};

static long MAX = 30L;

int main(int argc, char** argv) {

long double c = 0.0f;

for (int i=0; i < MAX; ++i)

for (int j=0; j<16;++j)

c += vec_a[j]* vec_a[j];

printf("%llf\n",c);

return 0;

}

[Bug c/54743] Large loop runs endingless

[slbyan at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54743

--- Comment #2 from 顏烈彬  2012-09-29 07:48:26 UTC ---
(In reply to comment #1)
You mean that i (as most INT_MAX) is always less than 300L?
And, in a RH 2.6.18-164.el5, gcc Red Hat 4.1.2-52, it runs as (was) expected,
because it's buggy is gcc 4.1.2?

> 30L is bigger than INT_MAX.

[Bug c/54743] Large loop runs endingless

[slbyan at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54743

--- Comment #3 from 顏烈彬  2012-09-29 07:49:12 UTC ---
(In reply to comment #1)
You mean that i (as most INT_MAX) is always less than 300L?
And, in a RH 2.6.18-164.el5, gcc Red Hat 4.1.2-52, it runs as (was) expected,
because it's buggy is gcc 4.1.2?

> 30L is bigger than INT_MAX.

[Bug c++/53666] New: -std=c++0x cause cc1plus to eat up RAM

[slbyan at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=53666

 Bug #: 53666
   Summary: -std=c++0x cause cc1plus to eat up RAM
Classification: Unclassified
   Product: gcc
   Version: 4.6.3
Status: UNCONFIRMED
  Severity: normal
  Priority: P3
 Component: c++
AssignedTo: unassig...@gcc.gnu.org
ReportedBy: slb...@gmail.com


I have a line of code "static std::bitset<0X7FFFULL> bitSetPL;" in
main.cpp, a simple programme . It's wired to pass gcc with flag -std=c++0x,
even if no manipulation upon bitSetPL. It makes cc1plus to eat up memory :-(,
but it goes well if flag -std=c++0x removed.