On Sun, Dec 16, 2018 at 06:13:57PM +0200, Dimitar Dimitrov wrote:
> - /* Clobbering the STACK POINTER register is an error. */
> + /* Clobbered STACK POINTER register is not saved/restored by GCC,
> + which is often unexpected by users. See PR52813. */
> if (overlaps_hard_reg_set_p (regset, Pmode, STACK_POINTER_REGNUM))
> {
> - error ("Stack Pointer register clobbered by %qs in %<asm%>", regname);
> + warning (0, "Stack Pointer register clobbered by %qs in %<asm%>",
> + regname);
> + warning (0, "GCC has always ignored Stack Pointer %<asm%> clobbers");
Why do we write Stack Pointer rather than stack pointer? That is really
weird. The second warning would be a note based on the first one, i.e.
if (warning ()) note ();
and better have some -W* option to silence the warning.
> is_valid = false;
> }
>
> diff --git a/gcc/testsuite/gcc.target/i386/pr52813.c
> b/gcc/testsuite/gcc.target/i386/pr52813.c
> index 154ebbfc423..644fef15fef 100644
> --- a/gcc/testsuite/gcc.target/i386/pr52813.c
> +++ b/gcc/testsuite/gcc.target/i386/pr52813.c
> @@ -5,5 +5,5 @@
> void
> test1 (void)
> {
> - asm volatile ("" : : : "%esp"); /* { dg-error "Stack Pointer register
> clobbered" } */
> + asm volatile ("" : : : "%esp"); /* { dg-warning "Stack Pointer register
> clobbered.\+GCC has always ignored Stack Pointer 'asm' clobbers" } */
> }
> --
> 2.11.0
>
Jakub
