Register overflow problem

[root at uokmet.UUCP]

Why do I get the register overflow in the following example:

# cat a4.c
main()
{
	register int i,j,k;
	float ag[5][5],dummy,xxx;

	dummy = ag[i][j] + xxx;
}
# cc -c a4.c
6: Register overflow: simplify expression
6: Register overflow: simplify expression
# pcc -c a4.c
# cat a5.c
main()
{
	register int i,j;
	float ag[5][5],dummy,xxx;

	dummy = ag[i][j] + xxx;
}
# cc -c a5.c
# diff a4.c a5.c
3c3
< 	register int i,j,k;
---
> 	register int i,j;


I've tried different variable names.  No difference.  The computer is a
PDP 11/44 running 2.9bsd.

	Kevin W. Thomas
	Univ. of Oklahoma
	School of Meteorology
	Norman, OK  73019

UUCP:	ihnp4!occrsh!uokmet!kwthomas	ihnp4!okstate!uokmax!uokmet!kwthomas