Segher Boessenkool <seg...@kernel.crashing.org> writes:
> On Fri, Apr 07, 2017 at 10:39:03AM +0200, Eric Botcazou wrote:
>> > Or we could just change "blockage" and wait for the next bug report.
>>
>> That's my suggestion, yes.
>>
>> > Alternatively, we can arrange for the bypass functions to not ICE. We
>> > can do that specific to these rs6000 pipeline descriptions, by having
>> > our own version of store_data_bypass_p; or we can make that function
>> > work for all insns (its definition works fine for insn pairs where
>> > not both the producer and consumer are SETs). That's what Kelvin's
>> > patch does. What is the value in ICEing here?
>>
>> Telling the back-end writer that something may be wrong somewhere instead of
>> silently accepting nonsense?
>
> Why is it nonsense? The predicate gives the answer to the question
> "given these insns A and B, does A feed data that B stores in memory".
> That is a perfectly valid question to ask of any two insns.
Agreed FWIW, but for:
@@ -3701,7 +3704,8 @@ store_data_bypass_p (rtx_insn *out_insn, rtx_insn
if (GET_CODE (out_exp) == CLOBBER)
continue;
- gcc_assert (GET_CODE (out_exp) == SET);
+ if (GET_CODE (out_exp) != SET)
+ return false;
if (reg_mentioned_p (SET_DEST (out_exp), SET_DEST (in_set)))
return false;
how about instead changing the CLOBBER check so that we continue
when it isn't a SET? That would allow things like UNSPECs and
USEs as well.
Thanks,
Richard
