Ok, done.

Pushed.

Aldy

On Sun, Nov 14, 2021 at 2:53 PM Martin Liška <mliska@suse.cz> wrote:
>
> On 11/14/21 14:15, Aldy Hernandez wrote:
> > The code computing ranges in PHIs in the path solver reuses the
> > temporary ssa_global_cache by calling its clear method.  Calling it on
> > an empty cache causes us to call memset with NULL.
> >
> > [The testcase doesn't fail without the patch.  I suppose it needs some
> > usbsan magic, or to live somewhere else?]
>
> Well, the actual test-case is the compiler itself as the source code.
> Anyway, the UBSAN error happens for thousands of test-cases when run
> during bootstrap-ubsan.mk config file. That said, I would remove
> the added test-case.
>
> Cheers,
> Martin
>
> >
> > Tested on x86-64 Linux.
> >
> > gcc/ChangeLog:
> >
> >       PR tree-optimization/103229
> >       * gimple-range-cache.cc (ssa_global_cache::clear): Do not pass
> >       null value to memset.
> >
> > gcc/testsuite/ChangeLog:
> >
> >       * gcc.dg/pr103229.c: New test.
> > ---
> >   gcc/gimple-range-cache.cc       |  3 ++-
> >   gcc/testsuite/gcc.dg/pr103229.c | 10 ++++++++++
> >   2 files changed, 12 insertions(+), 1 deletion(-)
> >   create mode 100644 gcc/testsuite/gcc.dg/pr103229.c
> >
> > diff --git a/gcc/gimple-range-cache.cc b/gcc/gimple-range-cache.cc
> > index a63e20e7e49..b347edeb474 100644
> > --- a/gcc/gimple-range-cache.cc
> > +++ b/gcc/gimple-range-cache.cc
> > @@ -651,7 +651,8 @@ ssa_global_cache::clear_global_range (tree name)
> >   void
> >   ssa_global_cache::clear ()
> >   {
> > -  memset (m_tab.address(), 0, m_tab.length () * sizeof (irange *));
> > +  if (m_tab.address ())
> > +    memset (m_tab.address(), 0, m_tab.length () * sizeof (irange *));
> >   }
> >
> >   // Dump the contents of the global cache to F.
> > diff --git a/gcc/testsuite/gcc.dg/pr103229.c b/gcc/testsuite/gcc.dg/pr103229.c
> > new file mode 100644
> > index 00000000000..96ef9aff67c
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.dg/pr103229.c
> > @@ -0,0 +1,10 @@
> > +// { dg-do compile }
> > +// { dg-options "-O -w" }
> > +
> > +int main() {
> > +  int i;
> > +  for (; i;)
> > +    ;
> > +
> > +  return 0;
> > +}
> >
>