Hi Christophe On 10/12/2019 09:01, Christophe Lyon wrote: > Hi, > > On Mon, 9 Dec 2019 at 11:23, Sudakshina Das <sudi....@arm.com> wrote: >> >> Hi Jeff >> >> On 07/12/2019 17:44, Jeff Law wrote: >>> On Fri, 2019-12-06 at 14:05 +0000, Sudakshina Das wrote: >>>> Hi >>>> >>>> While looking at the vectorization for following example, we >>>> realized >>>> that even though vectorizable_shift function was distinguishing >>>> vector >>>> shifted by vector from vector shifted by scalar, while modeling the >>>> cost >>>> it would always add the cost of building a vector constant despite >>>> not >>>> needing it for vector shifted by scalar. >>>> >>>> This patch fixes this by using scalar_shift_arg to determine whether >>>> we >>>> need to build a vector for the second operand or not. This reduces >>>> prologue cost as shown in the test. >>>> >>>> Build and regression tests pass on aarch64-none-elf and >>>> x86_64-pc-linux-gnu-gcc. This gives a 3.42% boost to 525.x264_r in >>>> Spec2017 for AArch64. >>>> > > Looks like you didn't check on arm, where I can see that the new testcase > fails: > FAIL: gcc.dg/vect/vect-shift-5.c -flto -ffat-lto-objects > scan-tree-dump vect "vectorizable_shift > ===[\\n\\r][^\\n]*prologue_cost = 0" > FAIL: gcc.dg/vect/vect-shift-5.c scan-tree-dump vect > "vectorizable_shift ===[\\n\\r][^\\n]*prologue_cost = 0" > > Seen on arm-none-linux-gnueabihf > --with-mode arm > --with-cpu cortex-a9 > --with-fpu neon-fp16 > > Christophe
Thanks for reporting this. There is already a bugzilla report PR92870 for powerpc that I am looking at. Apologies I couldn't find your email address there to add you to the cc list. Thanks Sudi > >>>> gcc/ChangeLog: >>>> >>>> 2019-xx-xx Sudakshina Das <sudi....@arm.com> >>>> Richard Sandiford <richard.sandif...@arm.com> >>>> >>>> * tree-vect-stmt.c (vectorizable_shift): Condition ndts for >>>> vect_model_simple_cost call on scalar_shift_arg. >>>> >>>> gcc/testsuite/ChangeLog: >>>> >>>> 2019-xx-xx Sudakshina Das <sudi....@arm.com> >>>> >>>> * gcc.dg/vect/vect-shift-5.c: New test. >>> It's a bit borderline, but it's really just twiddling a cost, so OK. >> >> Thanks :) Committed as r279114. >> >> Sudi >> >>> >>> jeff >>> >>
