On Tue, 19 May 2020, Uros Bizjak wrote:
> Hello!
>
> Attached patch adds missing vector zero/sign_extend expanders to allow
> vectorization of operations between different vector sizes.
>
> The patch regresses (progresses?):
>
> FAIL: gcc.target/i386/pr92645-4.c scan-tree-dump-times optimized
> "vec_unpack_lo" 3
>
> but eyeballing the asm code before/after the patch, we get much better:
>
> .L3:
> - vmovdqu (%rsi,%rax), %xmm6
> - vpxor %xmm5, %xmm5, %xmm5
> - vmovdqa %ymm5, -32(%rsp)
> - vmovdqa %xmm6, -32(%rsp)
> - vpmovzxbw -32(%rsp), %ymm0
> + vpmovzxbw (%rsi,%rax), %ymm0
> vpmullw %ymm4, %ymm0, %ymm0
> vpaddw %ymm2, %ymm0, %ymm0
> vpsrlw $8, %ymm0, %ymm0
>
> and even more differences to a much better code in the loop prologue.
>
> (Please note a strange double-save to a stack slot in the old code).
>
> Richi, I guess that the testcase you introduced needs some adjustment.
I will deal with the FAIL once you commit the patch, the testcase
is for forwprop code which indeed also knows how to exercise those
missing patterns. IIRC I filed the PR when working on those
(and may in turn remove the VEC_UNPACK_* support from forwprop again!)
> As discussed in the PR, there are a couple of XFAILs, where the
> compiler is not able to vectorize the code. The named expanders are
> there, but for the reason, explained in PR comment #8, middle-end
> doesn't exercise them.
OK, so we should track this in a separate PR? Can you point to
the specific expander and the XFAILed testcases there?
Thanks a lot!
Richard.
> gcc/ChangeLog:
>
> 2020-05-19 Uroš Bizjak <ubiz...@gmail.com>
>
> PR target/92658
> * config/i386/sse.md (<code>v16qiv16hi2): New expander.
> (<code>v32qiv32hi2): Ditto.
> (<code>v8qiv8hi2): Ditto.
> (<code>v16qiv16si2): Ditto.
> (<code>v8qiv8si2): Ditto.
> (<code>v4qiv4si2): Ditto.
> (<code>v16hiv16si2): Ditto.
> (<code>v8hiv8si2): Ditto.
> (<code>v4hiv4si2): Ditto.
> (<code>v8qiv8di2): Ditto.
> (<code>v4qiv4di2): Ditto.
> (<code>v2qiv2di2): Ditto.
> (<code>v8hiv8di2): Ditto.
> (<code>v4hiv4di2): Ditto.
> (<code>v2hiv2di2): Ditto.
> (<code>v8siv8di2): Ditto.
> (<code>v4siv4di2): Ditto.
> (<code>v2siv2di2): Ditto.
>
> testsuite/ChangeLog:
>
> 2020-05-19 Uroš Bizjak <ubiz...@gmail.com>
>
> PR target/92658
> * gcc.target/i386/pr92658-sse4.c: New test.
> * gcc.target/i386/pr92658-avx2.c: New test.
> * gcc.target/i386/pr92658-avx512bw.c: New test.
>
> Patch si bootstrapped and regression tested on x86_64-linux-gnu {,-m32}.
>
> Uros.
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg,
Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)
