On Sun, Dec 01, 2019 at 03:43:37PM +0100, Jan Hubicka wrote:
> > PR target/92549
> > * config/i386/i386.md (peephole2 for *swap<mode>): New peephole2.
> >
> > * gcc.target/i386/pr92549.c: New test.
>
> It is very hard to get a testcase, unforutnately, but I got the
> following (locally non-reproducible) failure while building firefox with
> LTO+FDO:
>
> [task 2019-12-01T14:38:04.166Z] 14:38:04 INFO - 1080 | }
> [task 2019-12-01T14:38:04.166Z] 14:38:04 INFO - |
> [task 2019-12-01T14:38:04.166Z] 14:38:04 INFO - (insn 5555 1389 1390 41
> (parallel [
> [task 2019-12-01T14:38:04.166Z] 14:38:04 INFO - (set (reg:SI
> 24 xmm4 [orig:187 SR.3778 ] [187])
> [task 2019-12-01T14:38:04.166Z] 14:38:04 INFO - (reg:SI 23 xmm3 [orig:104
> SR.3780 ] [104]))
> [task 2019-12-01T14:38:04.166Z] 14:38:04 INFO - (set (reg:SI
> 23 xmm3 [orig:104 SR.3780 ] [104])
> [task 2019-12-01T14:38:04.166Z] 14:38:04 INFO - (reg:SI 24 xmm4 [orig:187
> SR.3778 ] [187]))
> [task 2019-12-01T14:38:04.166Z] 14:38:04 INFO - ])
> "/builds/worker/workspace/build/src/obj-firefox/dist/include/mozilla/WritingModes.h":1117:0
> 78 {*swapsi}
> [task 2019-12-01T14:38:04.167Z] 14:38:04 INFO - (nil))
> [task 2019-12-01T14:38:04.167Z] 14:38:04 INFO - during RTL pass: rnreg
>
> I guess the problem is that there is no xchange in SSE instruction set,
> so peephle needs to be more restrictive?
I'll have a look tomorrow.
Jakub
