Hello,
Hopefully this is the right email to report a bug.
When testing for the fallthrough attribute with clang-10, the test is failing with a false negative (e.g. it's failing for a different reason).
Here is the output of a config.log with the warnings that are being generated by clang-10
configure:31082: checking for __attribute__((fallthrough))
configure:31103: clang-10 -o conftest conftest.c >&5
conftest.c:232:46: warning: no case matching constant switch condition '0'
int foo( void ) {switch (0) { case 1: __attribute__((fallthrough)); case 2: break ; }};
^
conftest.c:232:106: warning: non-void function does not return a value [-Wreturn-type]
int foo( void ) {switch (0) { case 1: __attribute__((fallthrough)); case 2: break ; }};
^
2 warnings generated.
configure:31103: $? = 0
configure:31116: result: no
Looking at the ax_gcc_func_attribute.m4 file, the C code for the test is:
int foo( void ) {switch (0) { case 1: __attribute__((fallthrough)); case 2: break ; }};
I tested the following and this looks like it might be a possible fix:
void foo(int x) { switch(x) { case 1:__attribute__((fallthrough)); case 2: break ; }};
Cheyenne Wills