[Bug libstdc++/29286] [4.0/4.1/4.2/4.3 Regression] placement new does not change the dynamic type as it should

["gdr at cs dot tamu dot edu" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #125 from gdr at cs dot tamu dot edu  2007-05-23 14:22 -------
Subject: Re:  [4.0/4.1/4.2/4.3 Regression] placement new does not change the
dynamic type as it should

"rguenther at suse dot de" <gcc-bugzilla@gcc.gnu.org> writes:

[...]

| But you can still perform hoisting loads of incoming pointer arguments
| and sinking stores to incoming pointer arguments.  Please read comment 
| #105 and come up with a testcase where we wouldn't be allowed to do
| a useful transformation we do now.  So I believe making placement new
| work with our current scheme will severely pessimize placement new
| users, but if we slightly change rules for everyone we'll be all happy.

Update.

The only comment I have so far on the -core reflector is to the effect
that the reading that the program I posted earlier violates NO
aliasing rule.  I'll follow with the proposal to bring the rules in
line with recent C99 rules.

-- Gaby


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29286