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.