toolchain/48696: gcc crashes on loongson when optimizing

[macallan%netbsd.org@localhost]

>Number:         48696
>Category:       toolchain
>Synopsis:       gcc crashes on loongson when optimizing
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    toolchain-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Apr 01 10:20:01 +0000 2014
>Originator:     Michael
>Release:        6.99.39
>Organization:
>Environment:
NetBSD kilbeggan 6.99.39 NetBSD 6.99.39 (KILBEGGAN) #5: Sun Mar 30 15:39:17 EDT 
2014  ml@blackbush:/stuff/build/obj_evbmips/sys/arch/evbmips/compile/KILBEGGAN 
evbmips

>Description:
cc -pipe -march=loongson2f -O2   -o flops flops.c 
flops.c: In function 'main':
flops.c:641:4: warning: incompatible implicit declaration of built-in function 
'exit'
flops.c:642:1: internal compiler error: Bus error
Please submit a full bug report,
with preprocessed source if appropriate.
See  for instructions.
*** Error code 1

Stop.
make: stopped in /tmp/benchmarks/flops/work

This only happens when running on Loongson hardware itself ( I'll try other 
MIPS but I suspect they'll have the same problem ) - a cross-gcc targeting MIPS 
built from the same source running on sparc64 works just fine ( as in build.sh 
-m evbmips64-el )

The most recent, locally built binaries I could find on my gdium are from 
2013-05-21 so the problem must have been introduced after that.
>How-To-Repeat:
Try to compile anything with optimization enabled.
>Fix: