[sdcc-devel] [ sdcc-Bugs-2970351 ] Handling of non-local jump targets in peephole optimizer

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Bugs item #2970351, was opened at 2010-03-14 20:06
Message generated for change (Settings changed) made by spth
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Category: peephole optimizer
Group: None
Status: Open
Resolution: None
Priority: 5
Private: No
Submitted By: Claude Sylvain (claude60)
>Assigned to: Nobody/Anonymous (nobody)
Summary: Handling of non-local jump targets in peephole optimizer

Initial Comment:
- This is a peephole problem that seems to append when a function
  is referred from another module.

"sdcc -v" says:
				      +++
SDCC : mcs51/gbz80/z80/ds390/pic16/pic14/TININative/ds400/hc08 2.9.7 #5734 (Mar
13 2010) (CYGWIN)
				      +++


SDCC error message:
				      +++
/usr/local/sdcc/bin/sdcc  -mz80  --peep-asm -c isr.c -o obj/isr.rel
*** internal error: no label has entry for _isr_ace0 in labelRefCountChange peep
hole.
obj/isr.asm:55: Error: <u> undefined symbol encountered during assembly
removing obj/isr.rel
make: *** [obj/isr.rel] Error 1
				      +++


- I created a little project to track down this problem.  To reproduce the
  peephole problem, just type the following commands in project directory:
	make clean
	make

- I attached the project mentioned above in an archive.


Regards,

Claude Sylvain
csy...@el...
Electro-Technica inc.



----------------------------------------------------------------------

Comment By: Philipp Krause (spth)
Date: 2010-04-06 10:29

Message:
As a temporary workaround tail call optimizations has been disabled in
revision #5785. I'll leave this bug report open (with a more descriptive
title) until a real fix has been implemented (and tail call optimization
can be reenabled).

Philipp


----------------------------------------------------------------------

Comment By: Philipp Krause (spth)
Date: 2010-03-23 14:01

Message:
I have looked into this problem a bit. It is not specific to the Z80 port.

The problem is in buildLabelRefCountHash() in SDCCpeeph.c. This function
builds an index of all labels used in some asm code. However it only
includes labels that lie within that code, ignoring labels, that are only
referenced in there.

E.g.

foo:
call bar

will result in foo being put into the index, but not bar.

buildLabelRefCountHash() should include all labels in the index.

Philipp


----------------------------------------------------------------------

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