[Bug pch/13689] GGC PCH breaks aliasing

[dje at watson dot ibm dot com]

------- Additional Comments From dje at watson dot ibm dot com  2004-01-15 18:40 -------
Subject: Re:  GGC PCH breaks aliasing 

	The example in the original report ICEs (with Honza's patch) on
AIX due to an internal varray consistency check.  With the splay tree
implementation, we presumably gets zeroes for the data that was not stored
in PCH.

	If the zeroes represent to alias sets that alias with everything,
then the code will be correct but potentially missing optimizations.  If
we re-use those alias sets numbers, then we may perform incorrect
optimizations assuming that types or expressions do not alias.

David



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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13689