toolchain/56789: alpha build fails with internal compiler error

[gson%gson.org@localhost (Andreas Gustafsson)]

>Number:         56789
>Category:       toolchain
>Synopsis:       alpha build fails with internal compiler error
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    toolchain-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Apr 10 12:15:00 +0000 2022
>Originator:     Andreas Gustafsson
>Release:        NetBSD-current
>Organization:
  
>Environment:
System: NetBSD
Architecture: x86_64
Machine: amd64
>Description:

Cross-building NetBSD/alpha on NetBSD/amd64 fails with an internal
compiler error:

  /tmp/build/2022.04.08.21.48.19-alpha/src/usr.bin/xlint/lint1/cgram.y:2159:1: internal compiler error: in store_data_bypass_p_1, at recog.c:3714
   2159 | }
        | ^

The problem started with these commits (which is not to say there is
anything wrong with them - an internal compiler error is a bug in the
compiler by definition):

  2022.04.08.21.48.19 rillig src/tests/usr.bin/xlint/lint1/msg_048.c 1.4
  2022.04.08.21.48.19 rillig src/tests/usr.bin/xlint/lint1/msg_048.exp 1.4
  2022.04.08.21.48.19 rillig src/usr.bin/xlint/Makefile.inc 1.21
  2022.04.08.21.48.19 rillig src/usr.bin/xlint/lint1/decl.c 1.269

Logs:

  http://releng.netbsd.org/b5reports/alpha/commits-2022.04.html#2022.04.08.21.48.19

>How-To-Repeat:

>Fix: