[PATCH] [alpha] adjust MEM alignment for block move [PR115459] (was: Re: [PATCH v2] [PR100106] Reject unaligned subregs when strict alignment is required)

[Maciej W. Rozycki]

Hi Alexandre,

> >  This has regressed building the `alpha-linux-gnu' target, in libada, as 
> > from commit d6b756447cd5 including GCC 14 and up to current GCC 15 trunk:
> 
> > | Error detected around g-debpoo.adb:1896:8                                |
> 
> > I have filed PR #115459.
> 
> Thanks!
> 
> This was tricky to duplicate without access to an alpha-linux-gnu
> machine.  I ended up building an uberbaum tree with --disable-shared
> --disable-threads --enable-languages=ada up to all-target-libgcc, then I
> replaced gcc/collect2 with a wrapper script that dropped crt[1in].o and
> -lc, so that link tests in libada/configure would succeed without glibc
> for the target.  libada still wouldn't build, because of the missing
> glibc headers, but I could compile g-depboo.adb with -I pointing at a
> x86_64-linux-gnu's gcc/ada/rts build tree, and with that, at -O2, I
> could trigger the problem and investigate it.  And with the following
> patch, the problem seems to be gone.

 If you like, I'll share with you a pair of scripts I use to cross-compile 
Linux configurations.  No target system is required to build things and 
all is done based on git checkouts from the relevant upstream repos, which 
then bootstrap themselves using whatever compiler is locally available to 
bootstrap native GCC first and then going through the ususal steps to get 
a target cross-compiler.

> Maciej, would you be so kind as to give it a spin with a native
> regstrap?  TIA,

 I will certainly run regression-testing once the job I started yesterday 
has finished with my Alpha system, which should be fairly soon as it's 
already well into libstdc++ testing.

 I cannot make a native bootstrap however as I have only just set up my 
Alpha to run at all and it has a very rudimentary and outdated userland, 
suitable for remote regression testing only.  It's NFS-rooted too and due 
to a failure in my lab last month I may not be able to recover from before 
August it runs over backup 10Mbps Ethernet rather than intended 100Mbps 
FDDI, so I can imagine performance would be abysmal even if I brought the 
userland up to date.

 However Adrian (cc-ed) has recently told me he could be running all kinds 
of stuff with his Alpha.  Adrian, would you be able to verify Alexandre's 
proposed fix in a native regstrap?

 Thanks a lot for such a quick fix, and then making it in the first place!

  Maciej