./all.bash is failing with this:

TEST FAIL sync/atomic
make[1]: Entering directory `/home/fhs/go/tip/src/pkg/sync/atomic'
gotest -test.short -test.timeout=120
rm -f _test/sync/atomic.a
8g  -p sync/atomic -o _gotest_.8 doc.go  
8a asm_386.s
rm -f _test/sync/atomic.a
gopack grc _test/sync/atomic.a _gotest_.8 asm_386.8 
panic: runtime error: SIGILL: illegal instruction
[signal 0x4 code=0x2 addr=0x807b8a2 pc=0x807b8a2]

goroutine 22 [running]:
sync/atomic.StoreUint64(0x18602508, 0x0)
    /home/fhs/go/tip/src/pkg/sync/atomic/asm_386.s:141 +0xe
/home/fhs/go/tip/src/pkg/sync/atomic/_xtest_.TestStoreInt64(0x186174a0, 0x1863ac60)
    /home/fhs/go/tip/src/pkg/sync/atomic/atomic_test.go:530 +0x1c1
testing.tRunner(0x186174a0, 0x81a0c84, 0x0)
    /home/fhs/go/tip/src/pkg/testing/testing.go:156 +0x39
created by testing.RunTests
    /home/fhs/go/tip/src/pkg/testing/testing.go:200 +0x511

goroutine 1 [chan receive]:
testing.RunTests(0x8048c00, 0x81a0ba0, 0x1e)
    /home/fhs/go/tip/src/pkg/testing/testing.go:201 +0x53f
testing.Main(0x8048c00, 0x81a0ba0, 0x1e, 0x1e, 0x81a7228, ...)
    /home/fhs/go/tip/src/pkg/testing/testing.go:168 +0x49
main.main()
    /home/fhs/go/tip/src/pkg/sync/atomic/_testmain.go:58 +0x43

goroutine 2 [syscall]:
syscall.Syscall6()
    /home/fhs/go/tip/src/pkg/syscall/asm_linux_386.s:46 +0x27
syscall.Select(0x0, 0x0, 0x0, 0x0, 0x186002b0, ...)
    /home/fhs/go/tip/src/pkg/syscall/zsyscall_linux_386.go:1098 +0x69
syscall.Sleep(0x3b9aca00, 0x0, 0x0, 0x0)
    /home/fhs/go/tip/src/pkg/syscall/syscall_linux.go:189 +0x94
time.sysSleep(0x3b9aca00, 0x0, 0x0, 0x0)
    /home/fhs/go/tip/src/pkg/time/sys_unix.go:15 +0x31
time.sleeper(0x1, 0x0)
    /home/fhs/go/tip/src/pkg/time/sleep.go:128 +0x135
created by time.after
    /home/fhs/go/tip/src/pkg/time/sleep.go:109 +0x262
gotest: "./8.out -test.short=true -test.timeout=120" failed: exit status 2
make[1]: *** [testshort] Error 2
make[1]: Leaving directory `/home/fhs/go/tip/src/pkg/sync/atomic'
make: *** [sync/atomic.testshort] Error 1


Which compiler are you using (5g, 6g, 8g, gccgo)?

8g

Which operating system are you using?

Linux

Which revision are you using?  (hg identify)

ab4256049da2+ tip

Please provide any additional information below.

MFENCE instruction seems to be the offender. This is on an old x86 system without SSE2.