Building on NetBSD/VAX 10.0_RC1, Summary(?)

I think we get more attention on a VAX again, as it seems to be usable 
again, so I just did a cut&paste of two emails on

our latest thread to get the machines working again.

Thanks again to Greg & Kalvis (for sharing the details), and for sure to 
a lot of others for working on it!!!

Also attached to this email is the patch from Kalvis again, so it is 
easier to find ...

On 2023-12-07 22:39, Kalvis Duckmanton wrote:
> Hi all,
>
> I *think* I've worked out what the 'reload' pass has done when 
> compiling this test case, though I'm not sure that I understand it 
> well enough to be able to explain it properly.
> I'm not yet sure what the cause is, but I have noticed that the output 
> from g++'s 'reload' pass isn't correct.
> What seems to have happened is that the instructions to push argument 
> 3 have inherited the output reload of --%sp into %r1 from the 
> instructions pushing argument 5, but GCC hasn't noted that the pushl 
> $0 for argument 4 has also changed %sp so the output reload can't be 
> reused.
>
> There's a block of code in gcc/reload1.c which does invalidate old 
> output reloads; the attached patch adds to this block to invalidate a 
> reload of an output register if the output register is a reference to 
> memory using an autoincrement or autodecrement addressing mode.
>
> With the patch applied, I've been able to compile the test case using 
> the resulting native compiler, and a native build of NetBSD hasn't 
> failed yet, which is promising.  I have not applied any workarounds to 
> sancov.c or to tree-switch-conversion.c, and I'm also compiling GCC 
> with the default optimisation level (-O2; I haven't applied any of 
> Matthew's changes mentioned earlier).
>
> I've also applied this change to a copy of GCC 10.5.0 from upstream 
> and on amd64 at least there was no change to the regression test 
> results so I don't think this introduces any regressions.
>
> I'm curious to know if this will work for anyone else.
>
> cheers
>
> kalvis
>
>
On 2023-12-12 19:54, Greg Oster wrote:
>
> You don't need to get gcc12 -- You can just use the gcc that is with 
> the sources you fetch above.  Grab the patch that Kalvis posted on Dec 
> 7, and patch the source.
>
>> Get is from PKGSRC first & install, than start a "build.sh -V 
>> HAVE_GCC12"?
>
> Just use regular 'build.sh' - no need to specify a different compiler 
> once the compiler sources are patched...  e.g.:
>
>  cd /u1/builds/build1/src/
>  sh ./build.sh -U -u -m vax -D /u1/builds/build1/install/vax \
>     -R /u1/builds/build1/release
>
> if your sources are in /u1/builds/build1/src/.  (My build line is 
> actually:
>
>   sh ./build.sh -U -u -m vax -j 2 -V MAKECONF=/u1/builds/mk.conf \
>     -D /u1/builds/build3/install/vax -R /u1/builds/build3/release
>
> as the build line gets generated and run by a different script...)
>
> You'll want to have a healthy amount of swapspace setup... right now 
> I'd suggest 512MB or better.  And set your shell limts to something like:
>
> cputime      unlimited
> filesize     unlimited
> datasize     524288 kbytes
> stacksize    8192 kbytes
> coredumpsize 0 kbytes
> memoryuse    58296 kbytes
> memorylocked 19432 kbytes
> maxproc      148
> maxthread    2048
> openfiles    548
> sbsize       unlimited
> vmemoryuse   524288 kbytes
>
> (which I do with this, in csh:
> limit maxproc unlimited
> limit datasize unlimited
> limit stacksize unlimited
> limit coredumpsize 0
> limit openfiles unlimited
> limit vmemoryuse unlimited
> )
>
> If you don't bump the default limits up building certain files will 
> fail... with '-j 2' I needed over 512MB to get the build to not fail - 
> 1024MB seems better...
>
> Later...
>
> Greg Oster
>

diff --git a/external/gpl3/gcc.old/dist/gcc/reload1.c b/external/gpl3/gcc.old/dist/gcc/reload1.c
index 88f4727d5453..8d481071a12b 100644
--- a/external/gpl3/gcc.old/dist/gcc/reload1.c
+++ b/external/gpl3/gcc.old/dist/gcc/reload1.c
@@ -8377,6 +8377,43 @@ emit_reload_insns (class insn_chain *chain)
 		reg_last_reload_reg[out_regno + k] = 0;
 	    }
 	}
+
+#if AUTO_INC_DEC /* XXX KD */
+      /* Where an output register might be reloaded, and it is a
+         memory reference, and the address is auto-incremented, any
+         previously reloaded copy of the address must be
+         invalidated. */
+      if (i < 0
+          && rld[r].out != 0
+          && MEM_P (rld[r].out))
+        {
+          rtx out = XEXP (rld[r].out, 0); /* address expression */
+          enum rtx_code code = GET_CODE (out);
+
+          if (code != POST_INC && code != POST_DEC
+              && code != PRE_INC && code != PRE_DEC)
+            {
+              /* do nothing */
+            }
+          else
+            {
+              int out_regno = REGNO (XEXP (out, 0));
+              machine_mode mode = GET_MODE (XEXP (out, 0));
+
+              /* for the moment, handle only the case where out_regno
+                 is a hardware register */
+
+              if (HARD_REGISTER_NUM_P (out_regno))
+                {
+                  int k, out_nregs = hard_regno_nregs (out_regno, mode);
+
+                  for (k = 0; k < out_nregs; k++)
+                    reg_last_reload_reg[out_regno + k] = 0;
+                }
+            }
+        }
+#endif /* AUTO_INC_DEC */ /* XXX KD */
+
     }
   reg_reloaded_dead |= reg_reloaded_died;
 }