On Wed, 16 Nov 2016, Jeff Law wrote:
> On 10/28/2016 05:51 AM, Richard Biener wrote:
> >
> > These are the middle-end changes and additions to the testsuite.
> >
> > They are pretty self-contained, I've organized the changelog
> > entries below in areas of changes:
> >
> > 1) dump changes - we add a -gimple dump modifier that allows most
> > function dumps to be directy fed back into the GIMPLE FE
> >
> > 2) pass manager changes to implement the startwith("pass-name")
> > feature which implements unit-testing for GIMPLE passes
> >
> > 3) support for "SSA" input, a __PHI stmt that is lowered once the
> > CFG is built, a facility to allow a specific SSA name to be allocated
> > plus a small required change in the SSA rewriter to allow for
> > pre-existing PHI arguments
> >
> > Bootstrapped and tested on x86_64-unknown-linux-gnu (together with [1/2]).
> >
> > I can approve all these changes myself but any comments are welcome.
> My only worry would be ensuring that in the case where we're asking for a
> particular SSA_NAME in make_ssa_name_fn that we assert the requested name is
> available.
>
> ISTM that if it's > the highest current version or in the freelist, then we
> ought to be safe. If it isn't safe then we should either issue an error, or
> renumber the preexisting SSA_NAME (and determining if it's safe to renumber
> the preexisting SSA_NAME may require more context than we have).
An alternative interface would be to return NULL rather than asserting.
OTOH the single caller requesting a specific version first does a lookup
if the SSA name already exists, so it is safe.
Richard.
