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

[Jeff Law <law at redhat dot 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 âgob.decIgnoreOpFor.pN20_encoding_gob.Decoderâ:
> > ../../../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