| Summary: | [6 Regression] FAIL: gcc.dg/vect/vect-over-widen-3-big-array.c -flto -ffat-lto-objects scan-tree-dump-times vect "vect_recog_over_widening_pattern: detected" 2 | ||
|---|---|---|---|
| Product: | gcc | Reporter: | ktkachov |
| Component: | middle-end | Assignee: | Alan Lawrence <alan.lawrence.arm> |
| Status: | RESOLVED FIXED | ||
| Severity: | normal | CC: | nickc, rguenther |
| Priority: | P3 | Keywords: | missed-optimization |
| Version: | 6.0 | ||
| Target Milestone: | 6.0 | ||
| Host: | Target: | arm-none-eabi | |
| Build: | Known to work: | 5.2.0 | |
| Known to fail: | 6.0 | Last reconfirmed: | 2015-07-15 00:00:00 |
| Attachments: | Vectorizer dump | ||
|
Description
ktkachov
2015-07-15 11:01:13 UTC
I will have a look. Hmm, with a cross to arm-none-eabi and -O2 -ftree-vectorize I see grep 'vect_recog_over_widening_pattern: detected' t.c.146t.vect t.c:14:3: note: vect_recog_over_widening_pattern: detected: _130 = (signed short) patt_131; t.c:14:3: note: vect_recog_over_widening_pattern: detected: patt_128 = _129 << 3; t.c:14:3: note: vect_recog_over_widening_pattern: detected: _126 = (signed short) patt_127; t.c:14:3: note: vect_recog_over_widening_pattern: detected: patt_124 = _125 << 3; any other configury / option besides that required? Yes, 4 is also not 2, the other two are from t.c:14:3: note: ***** Re-trying analysis with vector size 8 and it doesn't vectorize at all because it doesnt' support unaligned loads. Please provide more information to reproduce with a cross or attach the vectorizer dump. Created attachment 37387 [details]
Vectorizer dump
Hi Richard,
Here is a dump from a failing testcase. This was from a toolchain configured as --target=arm-eabi built using today's FSF mainline sources.
Cheers
Nick
For some reason you get widening shifts recognized while I get them not supported by the HW (with the cross at -O2 -ftree-vectorize). -mfpu=neon doesn't help.
I still can't reproduce your dump file with
/space/rguenther/src/svn/trunk3/configure --target=arm-none-eabi
gcc> /cc1 -quiet t.c -O2 -ftree-vectorize -fdump-tree-vect-details -fno-vect-cost-model -fno-common -mfpu=neon -march=armv7-a
please advise further.
Also you might want to try if guarding the check with { target ! vect_widen_shift } and adding a variant for vect_widen_shift to scan for 1 occurence fixes the
testcase. That would make sense to me.
(In reply to Richard Biener from comment #4) > For some reason you get widening shifts recognized while I get them not > supported by the HW (with the cross at -O2 -ftree-vectorize). -mfpu=neon > doesn't help. > > I still can't reproduce your dump file with > > /space/rguenther/src/svn/trunk3/configure --target=arm-none-eabi > gcc> /cc1 -quiet t.c -O2 -ftree-vectorize -fdump-tree-vect-details > -fno-vect-cost-model -fno-common -mfpu=neon -march=armv7-a > Can you try adding -mfloat-abi=hard to the command line? On Tue, 19 Jan 2016, ktkachov at gcc dot gnu.org wrote:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66877
>
> --- Comment #5 from ktkachov at gcc dot gnu.org ---
> (In reply to Richard Biener from comment #4)
> > For some reason you get widening shifts recognized while I get them not
> > supported by the HW (with the cross at -O2 -ftree-vectorize). -mfpu=neon
> > doesn't help.
> >
> > I still can't reproduce your dump file with
> >
> > /space/rguenther/src/svn/trunk3/configure --target=arm-none-eabi
> > gcc> /cc1 -quiet t.c -O2 -ftree-vectorize -fdump-tree-vect-details
> > -fno-vect-cost-model -fno-common -mfpu=neon -march=armv7-a
> >
>
> Can you try adding -mfloat-abi=hard to the command line?
Thanks, that way it works. Just figured I can't test if
the suggested testsuite addition works though.
I can test on ARM ;), so taken - https://gcc.gnu.org/ml/gcc-patches/2016-01/msg01727.html. |