https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104597
Bug ID: 104597
Summary: LTO does not inline indirect call
Product: gcc
Version: 11.2.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: m.cencora at gmail dot com
Target Milestone: ---
Given following files:
// main.cpp
using intfunc = int (*)();
intfunc getIntFunc(int i);
namespace
{
int test()
{
auto func = getIntFunc(1);
return func();
}
}
int main()
{
return test();
}
// lib1.cpp
namespace
{
int getInt0()
{
return 0;
}
int getInt1()
{
return 1;
}
int getInt2()
{
return 2;
}
}
using intfunc = int (*)();
intfunc getIntFunc(int i)
{
if (i == 0)
{
return getInt0;
}
else if (i == 1)
{
return getInt1;
}
else if (i == 2)
{
return getInt2;
}
__builtin_abort();
}
and compilation with:
g++ -std=c++20 -Wall -Wextra -O3 -flto -fvisibility=hidden
-fvisibility-inlines-hidden -ffunction-sections -Wl,-gc-sections main.cpp
lib1.cpp -o test
Call to getInt1 does not get inlined:
Dump of assembler code for function main:
0x0000000000001040 <+0>: endbr64
0x0000000000001044 <+4>: jmp 0x1140 <_ZN12_GLOBAL__N_17getInt1Ev>
