Don't propagate for a more expensive reg-reg move.

Don't propagate for a more expensive reg-reg move.

For i386, it enables optimization like:

        vmovd   %xmm0, %edx
-       vmovd   %xmm0, %eax
+       movl    %edx, %eax

gcc/ChangeLog:

	PR rtl-optimization/104059
	* regcprop.cc (copyprop_hardreg_forward_1): Don't propagate
	for a more expensive reg-reg move.

gcc/testsuite/ChangeLog:

	* gcc.target/i386/pr104059.c: New test.