"[PATCH] cc1/f771 array overrun - x86 Floating Point"

[Jeffrey A Law]

  In message <309F4FC4705DC844987051A517E9E39BF5BCAD@red-pt-02.redmond.corp.mic
rosoft.com>you write:
  > This patch reflects an (at least partly) asymtomatic bug.  An out of
  > bounds array access is occurring with reasonable regularity.  In my
  > situation, upon occasion the access causes a SIGSEGV, just due to the
  > accidents of memory layout.  Otherwise, the access appears to be
  > benign, in that it seems to have no negative effect that I've detected,
  > but since I'm not sure what the variable involved is being used for,
  > I can't say for sure.
  > 
[ ... ]
  > (Properly, this should be an ASSERT, but I suspect that it would
  > NOT prove a popular choice until the underlying problem is fixed.)
[ ... ]
Make it conditional on ENABLE_CHECKING and make the compiler abort and
it might make sense to include it.  At that point it would probably make
sense to include your testcase too.

As for the fix, it may simply be best to call init_insn_lengths after
reg-stack has finished, but I haven't tried it.

jeff