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Date: Mon, 23 Aug 2021 14:02:46 +0200
From: Jan Hubicka <hubicka@ucw.cz>
To: Richard Biener <richard.guenther@gmail.com>
Cc: Martin =?iso-8859-2?Q?Li=B9ka?= <mliska@suse.cz>,
 GCC Patches <gcc-patches@gcc.gnu.org>
Subject: Re: [PATCH] IPA: MODREF should skip EAF_* flags for indirect calls
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Hi,
> 
> Why does it "punish" -fno-ipa-pta?  It merely "punishes" modref of
> no longer claiming that we do not alter the instruction stream pointed
> to by a->foo, sth that shouldn't be very common.

For example
struct a {
  void (*foo)();
  void *bar;
}
fn(struct a *a)
{
   a->foo();
}

With Maritn's patch we will drop EAF flags of A to NODIRECTESCAPE since 
we will think its derefernece is is used in all posible ways. 

With my patch we get NOT_RETURNED | NOESCAPE.
Still we will make PTA to think that whatever is pointed to by bar may
be clobbered and this seems unnecessary.

I have to look into ipa-pta how it haldnes the "instruction stream
clobbering". I was not aware it does something smart about indirect
calls.

Honza