No TBAA before ptr_derefs_may_alias_p?

Jakub Jelinek jakub@redhat.com
Mon Feb 3 09:59:00 GMT 2014


On Mon, Feb 03, 2014 at 09:51:01AM +0000, Bingfeng Mei wrote:
> If it is just for C++ placement new, why don't implement it as a lang_hook.
> Now other languages such as C have to be made conservative and produce worse
> code.

Even in C++ code you don't use placement new that often, so e.g. by having
the placement new explicit through some special GIMPLE statement in the IL,
you could e.g. just look if a particular function or loop contains any
placement new stmts (cached in struct function and loop?) and use TBAA if
it isn't there.

	Jakub



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