On 24.05.2023 11:01, Hongtao Liu wrote: > On Wed, May 24, 2023 at 3:58 PM Jan Beulich via Gcc <gcc@gcc.gnu.org> wrote: >> >> Hello, >> >> for a couple of years I was meaning to extend the use of these AVX512F >> insns beyond the pretty minimalistic ones there are so far. Now that I've >> got around to at least draft something, I ran into a couple of issues I >> cannot explain. I'd like to start with understanding the unexpected >> effects of a change to an existing insn I have made (reproduced at the >> bottom). I certainly was prepared to observe testsuite failures, but it >> ends up failing tests I didn't expect it would fail, and - upon looking >> at sibling ones - also ends up leaving intact tests which I would expect >> would then need adjustment (because of using the new alternative). >> >> In particular (all mentioned tests are in gcc.target/i386/) >> - avx512f-andn-si-zmm-1.c (and its AVX512VL counterparts) fails because >> for whatever reason generated code reverts back to using vpbroadcastd, >> - avx512f-andn-di-zmm-1.c, otoh, is unaffected (i.e. continues to use >> vpandnq with embedded broadcast), >> - avx512f-andn-si-zmm-2.c doesn't use the new 4th insn alternative when >> at the same time a made-up DI variant of the test (akin to what might >> be an avx512f-andn-di-zmm-2.c testcase) does. >> IOW: How is SI mode element size different here from DI mode one? Is >> there anything wrong with the 4th alternative I'm adding, or is this >> hinting at some anomaly elsewhere? > __m512i is defined as __v8di, when it's used for _mm512_andnot_epi32, > it's explicitlt converted to (__v16si) and creates an extra subreg > which is not needed for DImode cases. > And pass_combine try to match the below pattern but failed due to the > condition REG_P (operands[1]) || REG_P (operands[2]). Here I think you > want register_operand instead of REG_P.
Thanks, this has indeed made things match my expectations wrt testsuite results. Sadly similar adjustments for other (new) insns didn't make any difference with the further issues I'm facing. I may therefore need to ask more questions; I hope they're not going to be too dumb. Jan
