Re: [PATCH] RISC-V: Fix ICE of visiting non-existing block in CFG.

[Richard Sandiford <richard.sandiford@arm.com>]

Jeff Law via Gcc-patches <gcc-patches@gcc.gnu.org> writes:
> On 12/27/22 16:11, juzhe.zhong wrote:
>> You mean only change to this form you suggested in this patch？ Since in 
>> all other places of this PASS，I use RTL_SSA framework to iterate 
>> instructions and blocks. I use RTL_SSA framework to iterate blocks here 
>> to make codes look more consistent even though they are same here.
> The FOR_EACH_BB is used far more widely than the C++ style found in 
> RTL-SSA so I'd slightly prefer that style.

I can see where you're coming from, but what the patch does is preferred
for RTL-SSA passes.  There is some additional information in
rtl_ssa::bb_info compared to the underlying basic_block, and even if
this particular loop doesn't use that information, IMO it would be
better to avoid mixing styles within a pass.

Also, the list that the patch iterates over is in reverse postorder,
whereas FOR_EACH_BB doesn't guarantee a particular order.  Again,
that might not be important here, but it seems better to stick to the
“native” RTL-SSA approach.

Thanks,
Richard