------- Comment #32 from mark at codesourcery dot com 2007-05-02 21:41 ------- Subject: Re: [4.0/4.1/4.2/4.3 Regression] placement new does not change the dynamic type as it should
ian at airs dot com wrote: > Here is one approach which fixes the test case. This introduces a new tree > code, ALIASING_CONVERT_EXPR. It is conveyed into RTL via a flag on REGS: > REG_ALIAS_ALL. I didn't try to really union the alias sets, I just said that > the result of placement new can alias anything. This patch is essentially > untested. I think this is a reasonable approach I agree that it will require care to make sure this is threaded through the compiler in all places (for example, we may need variants of STRIP_NOPs that do/don't strip it), but anything else is going to be too pessimistic. I think that creating a separate type, with TYPE_REF_CAN_ALIAS_ALL set, is worse: it's not the type of the expression that matters, but the action of the expression itself. It's the act of placement-newing that destroys type information; after that, the type that you have is what you expect. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=29286
