[Bug debug/91929] missing inline subroutine information in build using sin/cos

[rguenther at suse dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91929

--- Comment #13 from rguenther at suse dot de <rguenther at suse dot de> ---
On Fri, 18 Oct 2019, dimhen at gmail dot com wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91929
> 
> Dmitry G. Dyachenko <dimhen at gmail dot com> changed:
> 
>            What    |Removed                     |Added
> ----------------------------------------------------------------------------
>                  CC|                            |dimhen at gmail dot com
> 
> --- Comment #12 from Dmitry G. Dyachenko <dimhen at gmail dot com> ---
> I see new warnings -Wuninitialized and -Wmaybe-uninitialized after r276993
> 
> r276992 no warnings
> r276993 warnings
> 
> $ cat x_3.i
> int *a;
> int b, d;
> 
> int g() {
>   int *c;
>   int e[6];
>   int f = 1;
>   if (0)
>     goto cd;
>   c = 0;
>   for (; d; d++)
>     *e = 1 ^ *(c + 1);
>   if (f)
>     for (b = 0;;)
>       a[0] = e[b];
> cd:
>   return 0;
> }
> 
> $ ~/arch-gcc/gcc_276993/bin/gcc -fpreprocessed -O2 -Wall -c x_3.i
> 
> x_3.i: In function ‘g’:
> x_3.i:15:15: warning: ‘e[0]’ may be used uninitialized in this function
> [-Wmaybe-uninitialized]
>    15 |       a[0] = e[b];
>       |              ~^~~

If d is zero then e[0] will be loaded uninitialized.  PRE exposes
this to the uninit machinery which previously gave up for loops
by commoning e[b] with the set in the loop plus inserting
a load from e[0] on the path not coming from the loop.  I guess
previously the uninit pass didn't emit warnings for the load
because it had no location.

> $ cat x.i
> typedef struct {
>   int a[0];
> } c;
> typedef struct {
>   c d;
> } * e;
> e a;
> void f(void);
> void f() {
>   int c[1];
>   for (;;) {
>     unsigned long d[0];
>     int b, g, h = b = h;
>     unsigned long *e = d;
>     for (; g; ++g)
>       e[g] = 0;
>     *a->d.a = *c;
>   }
> }
> 
> $ ~/arch-gcc/gcc_276993/bin/gcc -fpreprocessed -O2 -Wall -c x.i
> x.i: In function ‘f’:
> x.i:17:13: warning: ‘c[0]’ is used uninitialized in this function
> [-Wuninitialized]
>    17 |     *a->d.a = *c;
>       |     ~~~~~~~~^~~~

This is the same (and g is not initialized here as well)