Re: [PATCH,testsuite] fix gcc.dg/tree-ssa/20030714-1.c with -fPIC

[Richard Guenther <rguenther@suse.de>]

On Wed, 23 Jan 2008, Kaveh R. GHAZI wrote:

> The testcase gcc.dg/tree-ssa/20030714-1.c is failing on the branches with
> -fpic/-fPIC and this failure is a regression (apparently intentional) from
> previous 4.x gcc.  More analysis below.
> 
> The test seems to rely on the code being automatically marked pure/const
> by gcc during compilation.  Mainline is okay because the failing scans in
> the test were removed as part of the fix for PR33826 by Kenny.  In that
> PR, it was decided that recursive function must not be considered for
> automatic pure/const marking.  So now the testcase on mainline passes
> regardless of pic or nonpic, because the checks have been truncated to fit
> into this new requirement.
> 
> On the branches, the testcase still does the original checks and gcc still
> allows recursive functions to become pure/const.  And it passes in the
> regular default case.  However a change was made by Richard G. to ensure
> this optimization happens only if the functions bind locally.  With
> -fpic/-fPIC the function doesn't bind locally and the error pops up.
> 
> Nathan proposed a fix to the testcase here in July:
> http://gcc.gnu.org/ml/gcc-patches/2007-07/msg01948.html
> but I don't see that it ever got reviewed or installed.
> 
> I believe Nathan's solution is correct in that he makes the function
> static so it binds locally.  By doing so, (and using a global wrapper to
> get the dump) it works for -fpic/-fPIC.
> 
> Another option would be to backport Kenny's patch for PR33826 which as a
> side-effect would cure this failure by removing the scans.  This might be
> the correct thing to do given the analysis in the PR, however it is also
> more intrusive.  I haven't bootstrapped Kenny's patch on the branches to
> make sure it doesn't break anything, but I will if people think it's a
> better option.
> 
> Thoughts on the best way to go?

Backporting Kennys patch is the right thing to do - I don't know
why the PR was closed as fixed.

Thanks,
Richard.