Date: Mon, 1 Mar 93 12:40:03 EST
From: ronis AT onsager DOT chem DOT mcgill DOT ca (David Ronis)
To: djgpp AT sun DOT soe DOT clarkson DOT edu
Subject: Bug with -funroll-loops in gcc

Hi DJ,

I have finally isolated a small code fragment that causes gcc to crash
on my PC when I turn on -funroll-loops.

The following when compiled with:

gcc -O2 -m486 -funroll-loops -c test.c

will crash with a segmentation violation (specifically, in pointer
0x00000000 at 40:819ea, exception 14 (0xe) at eip=819ea).

Removing the -funroll-loops flag "fixes" the problem.  Note,
that I use this flag eleswhere without any problem.

Thanks in advance.

David Ronis

-----------------------------------Cut Here------------------------------------



#include <stdio.h>
#define MAXMOMENTS	2

extern unsigned int nmonomer;
extern unsigned long count;
extern double *moment[];
extern int ivers;

void dump_run(string)
char *string;
{
	FILE *outstream;

	unsigned int i,j;
	float tmp[MAXMOMENTS+2];


	outstream=fopen("mmonte","wb");

	for(i=1;i<=nmonomer;i++){
		tmp[0]=i;
		for(j=0;j<MAXMOMENTS;j++)
			tmp[j+1]=(moment[j][i]/(double)count);
		tmp[MAXMOMENTS+1]=(tmp[1]-tmp[0]*tmp[0]);
		fwrite(tmp,sizeof(float),MAXMOMENTS+2,outstream);
	}
	fclose(outstream);

}