misleading message when failing to insert a pass...

[Basile Starynkevitch <basile at starynkevitch dot net>]

Hello All

(I've found this issue with the GCC MELT branch rev 169469, but I strongly
believe it is not directly related to MELT and should happen with the trunk
also. You could run the testsuite/melt/topengpu-1.c test, a comment in that
file describes how to run the test)

First, a pass inserted by a plugin (or a MELT module) into the pass tree has
to be of the same type. So a GIMPLE_PASS can only be inserted before or
after another GIMPLE pass, a SIMPLE_IPA_PASS can only be be inserted near a
SIMPLE_IPA_PASS, and an IPA_PASS can only be inserted near an IPA_PASS.

In particular, I find a bit confusing that a SIMPLE_IPA_PASS provided by a
plugin cannot be inserted after an IPA_PASS.

When one try to insert a pass with a kind mismatch, the error message is
very confusing. For instance, I'm getting

cc1 : pass local-pure-const not found but is referenced by new pass
meltopengpu_detect

But the pass 'local-pure-const' does indeed exist. So at least, the error
message should be improved (but I imagine that it is too late to even bother
trying submit a patch to 4.6 trunk now, because we are probably in a stage
[3, 4, don't understand the numbering] which disallows that).

I believe that we should improve the error message. Maybe a message like
"pass <XXX> found but of incompatible kind with new pass <YYY>" could be
more understandable.

I also find confusing that the pass 'local-pure-const' is a GIMPLE_PASS in
file ipa-pure-const.c near line 1682 and the file is named ipa*.c (which
suggest an IPA_PASS or SIMPLE_IPA_PASS) but that pass is just a GIMPLE_PASS.


Regards.
-- 
Basile STARYNKEVITCH         http://starynkevitch.net/Basile/
email: basile<at>starynkevitch<dot>net mobile: +33 6 8501 2359
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*** opinions {are only mines, sont seulement les miennes} ***