On 03-04-15 14:39, Tom de Vries wrote:
> On 27-03-15 15:10, Tom de Vries wrote:
>> Hi,
>>
>> this patch fixes PR65443, a todo in the parloops pass for function
>> transform_to_exit_first_loop:
>> ...
>>     TODO: the common case is that latch of the loop is empty and immediately
>>     follows the loop exit.  In this case, it would be better not to copy the
>>     body of the loop, but only move the entry of the loop directly before the
>>     exit check and increase the number of iterations of the loop by one.
>>     This may need some additional preconditioning in case NIT = ~0.
>> ...
>>
>> The current implementation of transform_to_exit_first_loop transforms the loop
>> by moving and duplicating the loop body. This patch transforms the loop into the
>> same normal form, but without the duplication, if that's possible (determined by
>> try_transform_to_exit_first_loop_alt).
>>
>> The actual transformation, done by transform_to_exit_first_loop_alt transforms
>> this loop:
>> ...
>>       bb preheader:
>>       ...
>>       goto <bb header>
>>
>>       <bb header>:
>>       ...
>>       if (ivtmp < n)
>>         goto <bb latch>;
>>       else
>>         goto <bb exit>;
>>
>>       <bb latch>:
>>       ivtmp = ivtmp + inc;
>>       goto <bb header>
>> ...
>>
>> into this one:
>> ...
>>       bb preheader:
>>       ...
>>       goto <bb newheader>
>>
>>       <bb header>:
>>       ...
>>       goto <bb latch>;
>>
>>       <bb newheader>:
>>       if (ivtmp < n + 1)
>>         goto <bb header>;
>>       else
>>         goto <bb exit>;
>>
>>       <bb latch>:
>>       ivtmp = ivtmp + inc;
>>       goto <bb newheader>
>> ...
>>
>
> Updated patch, now using redirect_edge_var_map and flush_pending_stmts.
>
> Bootstrapped and reg-tested on x86_64.
>
> OK for stage1 trunk?
>

Ping.

Thanks,
- Tom