Re: "insn does not satisfy its constraints" compiling perl

["Maciej W. Rozycki" <macro%orcam.me.uk@localhost>]

On Tue, 3 Mar 2026, Kalvis Duckmanton wrote:

> > There were many improvements in the vax backend which is why I think that
> > chances are the issue was actually fixed.
> > 
> > Did you check the GCC commit history whether there is a related change?
> 
> My suspicion is based upon the observation that the constraints on
> '*extzv_aligned' are the same in GCC 15 and GCC 14 (and GCC 12).  I agree that
> there is some change which is preventing this problem from reappearing in GCC
> 14.
> 
> I haven't checked the GCC history between version 12 and version 14 yet; I
> will check as suggested :)

 Either bisecting for where things have progressed or converting the case 
to an RTL test, perhaps starting with `expand', might help figuring out 
whether the issue has been fixed for real rather than papered over by 
other changes.  Search for `__RTL' in the GCC internals manual and/or have 
a look at e.g. commit 5a874dec6006 ("RISC-V/testsuite: Add RTL cset-sext.c 
testcase variants").

 I'm a bit swamped in the coming days, but please ping me if you need more 
information.

  Maciej