On Sat, 4 May 2019, Richard Sandiford wrote:
> Richard Biener <rguent...@suse.de> writes:
> > On Fri, 3 May 2019, Richard Biener wrote:
> >
> >>
> >> I am testing the following patch to remove the code determining
> >> the target virtual operand to walk to and instead compute it
> >> based on the immediate dominator which we will reach anyways
> >> (or a dominating block) during maybe_skip_until.
> >>
> >> More simplifying might be possible but I'm trying to keep the
> >> patch small and suitable for backporting up to the GCC 8 branch
> >> where this regressed.
> >>
> >> Note this will handle even more CFG shapes now and seems to
> >> expose some uninit warnings in dwarf2out.c (at least).
> >
> > I can't seem to find an initializer that would "trap" on use
> > so I'm going to do
> >
> > Index: gcc/dwarf2out.c
> > ===================================================================
> > --- gcc/dwarf2out.c (revision 270849)
> > +++ gcc/dwarf2out.c (working copy)
> > @@ -15461,7 +15461,7 @@ mem_loc_descriptor (rtx rtl, machine_mod
> > if (mode != GET_MODE (rtl) && GET_MODE (rtl) != VOIDmode)
> > return NULL;
> >
> > - scalar_int_mode int_mode, inner_mode, op1_mode;
> > + scalar_int_mode int_mode = SImode, inner_mode, op1_mode;
> > switch (GET_CODE (rtl))
> > {
> > case POST_INC:
> >
> > unless somebody comes up with something clever over the weekend...
>
> Nothing clever, but something rare like BImode is probably safer than
> SImode, in case doing this masks real "uninitialised" uses in future.
Ick, and I forgot to install this hunk when I committed it this morning.
Thus fixed as obvious now, with BImode.
Richard.
