Flag -fomit-frame-pointer cause seg fault

Hi All,
I am running a code under g++, which has been running fine with the flags:

Code:

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CXXFLAGS= -O3 -funroll-all-loops -ffast-math

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But as I add -fomit-frame-pointer to get:

Code:

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CXXFLAGS= -O3 -funroll-all-loops -fomit-frame-pointer -ffast-math

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then the program gives a segmentation fault. Unfortunately this flag also removes the trace so I don't know how to track it.

Any ideas?

Thanks,
Dave

Aftersome searching it seems the problem may be to do with the fact that I am running on Cygwin.

See:
http://cygwin.com/ml/cygwin/2001-04/msg01914.html

If anyone knows how to work around it I would be grateful.

D

The post is 6 years old. I think it's a fair assumption that the bug is corrected. What is more likely is that you have some undefined behaviour that is uncovered by omitting the frame pointer.

First, see if the problem still occurs if you remove all optimization flags but omit-frame-pointer. Then, add -g to the minimal set of flags that show the problem and see if it persists. If it does, run the program under gdb and get a stack trace.

Quote:

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Originally Posted by CornedBee

First, see if the problem still occurs if you remove all optimization flags but omit-frame-pointer. Then, add -g to the minimal set of flags that show the problem and see if it persists. If it does, run the program under gdb and get a stack trace.

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-fomit-frame-pointer == no stack trace

My GCC disagrees. Might be different for MinGW.

Code:

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void f();
void g();
void h();
void i();

int main()
{
  f();
  return 0;
}

void f() { g(); }
void g() { h(); }
void h() { i(); }

void i()
{
  int *p = 0;
  *p = 1;
}

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Code:

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$ cc -fomit-frame-pointer -o trace trace.c
$ gdb trace
(gdb) run
Starting program: /home/wasti/projects/test/trace

Program received signal SIGSEGV, Segmentation fault.
0x00000000004004f7 in i ()
(gdb) bt
#0  0x00000000004004f7 in i ()
#1  0x00000000004004e4 in h ()
#2  0x00000000004004d1 in g ()
#3  0x00000000004004be in f ()
#4  0x00000000004004a6 in main ()

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