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From: "i at maskray dot me" <gcc-bugzilla@gcc.gnu.org>
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Subject: [Bug tree-optimization/66512] PRE fails to optimize calls to pure
 functions in C++, ok in C
Date: Tue, 24 Nov 2020 23:44:41 +0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=3D66512

Fangrui Song <i at maskray dot me> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |i at maskray dot me

--- Comment #4 from Fangrui Song <i at maskray dot me> ---
Should this be reopened?

https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html 'const' =
is
not clarified on its interaction with threads
(https://gcc.gnu.org/legacy-ml/gcc/2015-09/msg00365.html)

and=20

void f()
{
  for (;;)
    g(p());
}

is still pessimized for C++ (I tend to agree that 'const' should imply
'nothrow'; even if no, the #c2 case should be resolved properly)=