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.
Thanks,
Richard
