Re: [PATCH] Fix middle-end/67133, part 1

[Jeff Law <law@redhat.com>]

On 08/20/2015 04:37 AM, Marek Polacek wrote:
> On Thu, Aug 20, 2015 at 11:02:17AM +0200, Andreas Schwab wrote:
>> Marek Polacek <polacek@redhat.com> writes:
>>
>>> 	PR middle-end/67133
>>> 	* gimple-ssa-isolate-paths.c
>>> 	(insert_trap_and_remove_trailing_statements): Rename to ...
>>> 	(insert_trap): ... this.  Don't remove trailing statements; split
>>> 	block instead.
>>> 	(find_explicit_erroneous_behaviour): Don't remove all outgoing edges.
>>
>> This breaks go on aarch64:
>>
>> ../../../libgo/go/encoding/gob/decode.go: In function ‘gob.decIgnoreOpFor.pN20_encoding_gob.Decoder’:
>> ../../../libgo/go/encoding/gob/decode.go:843:1: internal compiler error: in operator[], at vec.h:714
>>   func (dec *Decoder) decIgnoreOpFor(wireId typeId) decOp {
>>   ^
>> 0xac5c3b vec<edge_def*, va_gc, vl_embed>::operator[](unsigned int)
>>          ../../gcc/vec.h:714
>> 0xac5c3b extract_true_false_edges_from_block(basic_block_def*, edge_def**, edge_def**)
>>          ../../gcc/tree-cfg.c:8456
>> 0xace9bf gimple_verify_flow_info
>>          ../../gcc/tree-cfg.c:5260
>> 0x6ea1ab verify_flow_info()
>>          ../../gcc/cfghooks.c:260
>> 0xadeca3 cleanup_tree_cfg_noloop
>>          ../../gcc/tree-cfgcleanup.c:739
>> 0xadeca3 cleanup_tree_cfg()
>>          ../../gcc/tree-cfgcleanup.c:788
>> 0x9d21c3 execute_function_todo
>>          ../../gcc/passes.c:1900
>> 0x9d2b07 execute_todo
>>          ../../gcc/passes.c:2005
>
> Whilst I'm struggling with building cross libgo to reproduce this, is
> there something like preprocessed source for go?  So that ideally I'd
> just run ./go1 foo.go?  That'd help tremendously.
The process for finding out what Go's doing is, umm, exceedingly 
difficult.  Though at least for gcc-go, using "-v" will help.

RTH might have some ideas.


Based on the error, I suspect we've got a block ending with a 
GIMPLE_COND with no successors in the CFG.

jeff