Documentation clarificiation for gcc-7

[L A Walsh <gcc at tlinx dot org>]

Regarding the gcc-7 manpage, these options:

      -fsched-stalled-insns
      -fsched-stalled-insns=n
          Define how many insns (if any) can be moved prematurely from the
          queue of stalled insns into the ready list during the second
          scheduling pass.  -fno-sched-stalled-insns means that no 
insns are
          moved prematurely, -fsched-stalled-insns=0 means there is no 
limit
          on how many queued insns can be moved prematurely.
          -fsched-stalled-insns without a value is equivalent to
          -fsched-stalled-insns=1.

      -fsched-stalled-insns-dep
      -fsched-stalled-insns-dep=n
          Define how many insn groups (cycles) are examined for a 
dependency
          on a stalled insn that is a candidate for premature removal from
          the queue of stalled insns.  This has an effect only during the
          second scheduling pass, and only if -fsched-stalled-insns is 
used.
          -fno-sched-stalled-insns-dep is equivalent to
          -fsched-stalled-insns-dep=0.  -fsched-stalled-insns-dep without a
          value is equivalent to -fsched-stalled-insns-dep=1.

-------
In the 1st option, "<option>=0" equals "no limit" and -fno-<option> 
equals don't do any.

In the 2nd option, it says "-fno-<option> equals "<option>=0".  For this
option, does "<option>=0" also mean "no limit"?  If that is the case,
then does "-fno-<option> really mean "no limit"? 


For both, is there a default?  Are either options default at some
optimization level (O2/O3?)?  Are either enabled in the presence of
other -fsched options?  

Is there someplace or is there a document to read more about the
the other -fsched options, especially in relation to the Intel x86-64
architecture(s)?

Thanks!
linda