Rev 1.2 appears to have come from this commit to gcc-2.6.1:

Rev 1.2 appears to have come from this commit to gcc-2.6.1:

	phk         95/03/10 00:24:10

	Modified:    gnu/usr.bin/cc/cc_int final.c
	Since we are in the gcc bashing mood anyway:  Add two changes for
	basic-block profiling:
	1. use a .stabs(25) symbol to link all the data structures together
	with.  The regular method isn't safe for the kernel.
	2. add a BB before the prologue and add a BB after the epilogue,
	this alows us to find the length of any counted BB.  This is a
	cheap and somewhat reasonable measure of actual cost.

Note #1 was removed in rev 1.4.