[Bug lto/91988] Inlining fails with LTO enabled

[gcc-bugzilla at tobias dot goedderz.info]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91988

--- Comment #1 from Tobias Gödderz  
---
Happens with GCC 9.1.0 as well.

[Bug lto/91988] New: Inlining fails with LTO enabled

[gcc-bugzilla at tobias dot goedderz.info]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91988

Bug ID: 91988
   Summary: Inlining fails with LTO enabled
   Product: gcc
   Version: 8.3.0
Status: UNCONFIRMED
  Severity: normal
  Priority: P3
 Component: lto
  Assignee: unassigned at gcc dot gnu.org
  Reporter: gcc-bugzilla at tobias dot goedderz.info
CC: marxin at gcc dot gnu.org
  Target Milestone: ---

Inlining fails with LTO when there is an argument with a destructor. This seems
unintentional to me, given the following behaviour.

Given the following example files:

==> main.cpp <==
#include "lib.h"

int main() {
  return fun(A{});
}

==> lib.h <==
#ifndef LIB_H
#define LIB_H

class A { public: ~A() {} };

__attribute__((always_inline))
int fun(A);

#endif // LIB_H

==> lib.cpp <==
#include "lib.h"

__attribute__((always_inline))
int fun(A a) { return 0; }


and compiling with

/usr/bin/g++-8 -g -Wall -pedantic -O3 -std=c++14 -flto -c lib.cpp
/usr/bin/g++-8 -g -Wall -pedantic -O3 -std=c++14 -flto -c main.cpp
/usr/bin/g++-8 -g -Wall -pedantic -O3 -std=c++14 -flto -o main-gcc main.o lib.o

fails with
  error: inlining failed in call to always_inline ‘fun(A)’: mismatched
arguments
in the last step.

Removing "__attribute__((always_inline))" and inspecting the deassembled output
confirms that the function isn't inlined.

If the body is moved to the header file (and the "inline" specifier added), the
function is inlined.

If the destructor of "A" is removed, or changed to "~A() = default", the
function is inlined.

If the argument to "fun" is changed to a "const&", the function is inlined.

[Bug c++/91387] New: Segfault using -flto

[gcc-bugzilla at tobias dot goedderz.info]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91387

Bug ID: 91387
   Summary: Segfault using -flto
   Product: gcc
   Version: 8.3.0
Status: UNCONFIRMED
  Severity: normal
  Priority: P3
 Component: c++
  Assignee: unassigned at gcc dot gnu.org
  Reporter: gcc-bugzilla at tobias dot goedderz.info
  Target Milestone: ---

Created attachment 46684
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=46684=edit
Preprocessed source code

Hi,

I'm experiencing g++ segfaults during compilation. This is a "minimal" example
in terms of command line parameters, using the preprocessed source (which is
not minimal):

> $ /usr/bin/g++-8 -std=c++14 -O2 -flto -fno-devirtualize -c 
> ShapeContainerTest.ii
> during IPA pass: cp
> /home/tobias/Documents/ArangoDB/arangodb/arangodb/tests/Geo/ShapeContainerTest.cpp:
>  In function ‘arangodb::velocypack::Builder::openCompoundValue(unsigned char) 
> [clone .part.119]’:
> /home/tobias/Documents/ArangoDB/arangodb/arangodb/tests/Geo/ShapeContainerTest.cpp:427:2:
>  internal compiler error: Segmentation fault
>  }}
>   ^
> Please submit a full bug report,
> with preprocessed source if appropriate.
> See  for instructions.

This is with g++ (Ubuntu 8.3.0-6ubuntu1~18.04.1) 8.3.0.

I have two other files exhibiting a similar error, if it's of interest. The one
referenced above is attached.

Please tell me if and how I can be of further help.

Best regards,

Tobias