https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89325
Bug ID: 89325
Summary: False warnings about "optimization attribute" on
operators when -fno-ipa-cp-clone
Product: gcc
Version: 7.3.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: thehans at gmail dot com
Target Milestone: ---
Created attachment 45687
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=45687&action=edit
minimum test case
This is an issue I was having where g++ was outputting over 56,000 spurious
warnings for a project I was building.
I found that the problem only came from including Eigen/Core header amongst
various project headers that declared operators.
I was able to use singledelta to minimize the test case down to the attached
file.
After the #pragma which comes from Eigen, it seems to break g++'s ability to
differentiate between different operator signatures and just warns that they
are all previously defined with different attributes.
Here is the warning output from g++:
testcase-min.i:4:37: warning: optimization attribute on 'int& operator<<(int&,
const B&)' follows definition but the attribute doesn't match [-Wattributes]
int &operator<<(int &i, const B &ast);
^
testcase-min.i:1:35: note: previous definition of 'int& operator<<(int&, const
A&)' was here
class A { private: friend int &operator<<(int &i, const A &value) { return
i; } };
^~~~~~~~
