[Patch] Fix PR44328 - switch/case optimization produces an invalid lookup table index

[Ian Bolton]

H.J.Lu writes:
> > H.J.Lu writes:
> >> I am open to suggestions as to where it should go, and what
> >> > options to give it.
> >>
> >> gcc.dg?
> >>
> >> > For trunk, I need "-fstrict-enums -O2 -Wextra" to cause the
> >> > circumstances that exposed the bug, and check that there are
> >> > no warnings.  For 4.5 branch, -fstrict-enums does not exist,
> >> > so I guess I only want "-O2 -Wextra".
> >> >
> >>
> >> Only add -fstrict-enums to test in trunk.
> >>
> >
> > Thanks for your help.  As the test is a C++ one, I have added it
> > to testsuite/g++.dg, and updated the patch accordingly.
> >
> > Note that this is intended for 4.5 branch, as I have not
> > supplied -fstrict-enums in the test.
> >
> > Best regards,
> > Ian
> >
> >
> >
> > 2010-08-16  Ian Bolton  <ian.bolton@arm.com>
> >
> >        * tree-switch-conversion.c (gen_inbound_check): Ensure that
> the
> >        type for the conditional has wide enough range.
> >
> >        * testsuite/g++.dg/pr44328.C: New test.
> >
> 
> You should submit the patch for trunk first and backport to 4.5 branch
> after it was checked into trunk.

I have ran into trouble creating a test-case for trunk, because the
second invocation of tree_forwprop hides the issue.  I have hacked the
code to only allow the first pass of tree_forwprop and it can then be
seen that vrp1 erroneously turns <= 2 into != 3 due to having the wrong
type for the switch index.  (My fix prevents this from happening.)

What do you suggest I do with regards the patch for trunk?  Should I
include no test, or should I include the test I created for 4.5 branch,
even though it won't actually catch the trunk issue?

Best regards,
Ian