PLL input from non-dedicated clock pin

Hello all,

I've struck with a simple problem and I'm almost nearing the wall in terms of options.

I've a design in which the clock is coming from a non-dedicated clock pin (PIN_AJ16). I've to generate a divide-by-2 clock and I read in the forum the best way is to use PLL.

PLL can be driven from Global clock lines or dedicated clock pins. So, I instantiated a ALTCLKCTRL megafunction to route the pin on global clock line and then use that as input for the PLL. But, I still get the same error

Error: Can't place Top/Bottom or Left/Right PLL "sclkpll:u7|altpll:altpll_component|sclkpll_altpll:auto_generated|pll1" -- I/O pin ClkIn (port type INCLK of the PLL) is assigned to a location which is not connected to port type INCLK of any PLL on the device

Here is the code for the same

sclkctrl u1 (
	.inclk(ClkIn),
	.outclk(ClktoPLL));
sclkpll u2 (
	.inclk0(ClktoPLL),
	.c0(ClkfromPLL));

Its almost like the ALTCLKCTRL block has been removed by optimization. Can you suggest any alternatives?

Thanks,

Gopal