https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122507
Bug ID: 122507
Summary: undefined reference using inline assembly with LTO
Product: gcc
Version: 16.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: lto
Assignee: unassigned at gcc dot gnu.org
Reporter: peter0x44 at disroot dot org
Target Milestone: ---
For the following code:
#include <stdio.h>
extern int my_add(int x, int y);
__asm__(
".text \n"
".def my_add; .scl 3; .type 32; .endef \n"
//".globl my_add \n" ////////////////////////
"my_add: \n"
" lea eax, [rcx + rdx] \n"
" ret \n"
);
int
main(void)
{
printf("my_add(42, 1) = %d\n", my_add(42, 1));
}
compiled with:
x86_64-w64-mingw32-gcc test.c -flto -O2 -masm=intel
gives this undefined reference:
/home/peter/wintoolchain/lib/gcc/x86_64-w64-mingw32/16.0.0/../../../../x86_64-w64-mingw32/bin/ld:
/tmp/cc3Ozpev.ltrans0.ltrans.o:<artificial>:(.text.startup+0x14): undefined
reference to `my_add'
collect2: error: ld returned 1 exit status
reverting e7e91a83b85e1189e513ad14edb5e69d5bd25871 fixes it.
as does uncommenting:
//".globl my_add \n" ////////////////////////
or removing LTO.
