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From: "jamborm at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug ipa/108226] __restrict on inlined function parameters does not function as expected
Date: Fri, 17 Feb 2023 13:57:27 +0000	[thread overview]
Message-ID: <bug-108226-4-5QLJkedGQF@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-108226-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108226

--- Comment #2 from Martin Jambor <jamborm at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #1)
> 
> so somehow the restrict qualification pessimizes IPA-CP?!  Martin?
> 

Well, funny thing.  Without restrict, IPA-CP sees (from release_ssa dump):

void Func3 (char * p1, int * p2)
{
  <bb 2> [local count: 1073741824]:
  *p1_3(D) = 123;
  *p2_2(D) = 1;
  Func1 (p1_3(D), p2_2(D));
  return;
}

But with restrict in Func2 parameters, Func3 becomes:

void Func3 (char * p1, int * p2)
{
  <bb 2> [local count: 1073741824]:
  *p2_2(D) = 1;
  *p1_4(D) = 123;
  Func1 (p1_4(D), p2_2(D));
  return;
}

And the different ordering of the two stores is the problem, even when
p1 is not a char pointer, because we dont't trust the types of the
actual/formal parameters for TBAA (we would need to know in what types
they are read in Func1).

      parent reply	other threads:[~2023-02-17 13:57 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-26  0:05 [Bug tree-optimization/108226] New: " jhaberman at gmail dot com
2023-01-09 13:54 ` [Bug ipa/108226] " rguenth at gcc dot gnu.org
2023-02-17 13:57 ` jamborm at gcc dot gnu.org [this message]

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