http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42894
Jeffrey A. Law <law at redhat dot com> changed:
What |Removed |Added
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CC| |law at redhat dot com
--- Comment #16 from Jeffrey A. Law <law at redhat dot com> 2011-01-17 17:41:05
UTC ---
I agree with Jakub -- let's keep the set of CONST expressions which can be
shared small, well defined and limited to those which make a significant
difference in memory usage, code maintainability, etc.
I really don't see much to be gained by allowing these more generic forms --
and they run the real risk of causing bugs. Specifically, if we allow the
additional shared forms, then the middle end has to be prepared to deal with
fairly arbitrary CONST sharing created by the backends. Getting this wrong
results in wrong-code, segfaults and all kinds of ugly and hard to diagnose
bugs.
I guess the simplest way to summarize how I look at this is we need a
compelling reason to expand the set of shared CONST nodes.
I'd like to see Andrey's patch go in along with some updated documentation on
what CONST nodes can be shared.
