[Bug target/57018] [4.8/4.9 Regression] Miscompilation of bison 2.7.1 under "-Os -fomit-frame-pointer"

[vmakarov at redhat dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57018

Vladimir Makarov <vmakarov at redhat dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |vmakarov at redhat dot com

--- Comment #9 from Vladimir Makarov <vmakarov at redhat dot com> 2013-04-22 13:53:10 UTC ---
(In reply to comment #8)
> BTW, with reload on current trunk, bar has identical code, except for the right
> leal 32(%esp), %esi instead of the wrong leal 16(%esp), %esi.
> 
> It seems that with reload, elimination_effects is called both during IRA costs
> analysis and later on during actual elimination, while with LRA only IRA costs
> analysis calls it.  And I don't see code in lra-eliminations.c that would
> adjust ep->offset based on say sp adjustments in the code.

Yes, that is true.  In such cases LRA just prevents frame pointer elimination
(except for stack realingnment). I omitted this functionality as I thought it
is not that important for code majority. May be it is time to reconsider this
decision.

I have a patch for the PR which I'll commit today later after some testing.