[Bug tree-optimization/39604] [4.3/4.4/4.5 Regression] tree-ssa-sink breaks stack layout

[rguenther at suse dot de]

------- Comment #16 from rguenther at suse dot de  2009-05-10 14:14 -------
Subject: Re:  [4.3/4.4/4.5 Regression] tree-ssa-sink
 breaks stack layout

On Sun, 10 May 2009, steven at gcc dot gnu dot org wrote:

> ------- Comment #15 from steven at gcc dot gnu dot org  2009-05-10 13:51 -------
> The late stack slot allocation idea will just cause other problems, like
> missing CSE of addresses.  GCC should just get the conflicts right somehow...

"somehow..." ;)

I don't see how without making the coalescing decisions part of the IL
on RTL (and of course see if coalescing is even possible before doing it).

What about dropping all MEM_EXPRs for accesses to coalesced variables?
With the new memory-model that should be enough, without it you'd also
need to make the use alias set zero.

Richard.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39604