[Libclc-dev] [PATCH 1/9] RFC: Refactor clcmacro.h to vectorize without hi/lo

Aaron Watry awatry at gmail.com
Wed Jul 30 15:34:27 PDT 2014


LLVM: git 6800393083a4030 / svn r213860 (From 7/24)
CLANG: git 5ce5cbd836b3 / svn r213853
libclc: git a63df067faf8a / svn r213762 with the following two patches applied:

r600: Actually use vstore assembly optimizations
r600: improve float vload/vstore path

With that setup, and mesa 0ddc28b026688d, I get failures in the
float16 nextafter tests.

I'll give a shot at updating llvm/clang when I get home and see if
that helps things out.  I had noticed earlier today that Matt had
recently committed a bunch of vector load/store and alignment changes
(r214055 looks especially applicable), so maybe something in there did
the trick.

--Aaron

On Wed, Jul 30, 2014 at 3:39 PM, Tom Stellard <tom at stellard.net> wrote:
> On Sat, Jul 26, 2014 at 03:12:30PM -0500, Aaron Watry wrote:
>> On Fri, Jul 25, 2014 at 9:40 PM, Tom Stellard <tom at stellard.net> wrote:
>> > On Tue, Jul 22, 2014 at 08:46:42PM -0500, Aaron Watry wrote:
>> >> There are odd things happening with 16x vectors in nextafter() and sign().
>> >>
>> >> When I changed float16 load/store to use the assembly path in later
>> >> patches instead of the macro-vectorized version, nextafter and sign
>> >> stopped working (next 2 commits/patches).
>> >>
>> >> As near as I can tell, we're getting correct results for
>> >> elements 0-7, but then elements 8+ are wrong. The final result
>> >> seems to be composed of the first 8 elements of the computed
>> >> result, and then elements 16-23, which are likely uninitialized.
>> >>
>> >> I'd like to say the issue is in clang, but I have nothing to back
>> >> that up at the moment and give that this patch fixes the issue, I’m
>> >> not sure how much time I want to spend investigating right now.
>> >>
>> >> Explicitly splitting all of the vectorize macros the way that this patch
>> >> does gets everything working again, but I have a feeling that we're
>> >> papering over a bug somewhere, hence the RFC subject.
>> >>
>> >> I’m not sure what’s going on here, and it’s only the nextafter/sign
>> >> functions that regressed. This patch fixes the test results in piglit.
>> >>
>> >> No significant change on number of instructions in bitcode
>> >> for nextafter float16 (2-3 instructions savings over ~350 lines).
>> >>
>> >
>> > Were you testing this on Evergreen?  The sign() test passes for me on
>> > SI without this patch.
>> >
>>
>> I don't have my EG card available at the moment, but I *think* that
>> passed.  All I've got available at the moment is my pitcairn (si). For
>> me on pitcairn, I get failures in
>> piglit/generated_tests/cl/builtin/math/builtin-float-nextafter-1.0.generated.cl
>> for only the float16 type (about half of them pass, half don't).
>>
>
> This test passes for me too.  How current is your install of LLVM, I think there
> were some shufflevector fixes/improvements recently that may have fixed this test.
>
> -Tom
>
>> What happens if you test with [1] and [2] applied (enable vstore
>> optimizations and then add float to those optimizations), but without
>> the clcmacro refactoring patch [3]?
>>
>> [1] http://www.pcc.me.uk/pipermail/libclc-dev/2014-July/000461.html
>> [2] http://www.pcc.me.uk/pipermail/libclc-dev/2014-July/000462.html
>> [3] http://www.pcc.me.uk/pipermail/libclc-dev/2014-July/000460.html
>>
>> --Aaron
>>
>> > -Tom
>> >
>> >> Signed-off-by: Aaron Watry <awatry at gmail.com>
>> >> ---
>> >>  generic/lib/clcmacro.h | 84 +++++++++++++++++++++++++++++++++++++++++++-------
>> >>  1 file changed, 73 insertions(+), 11 deletions(-)
>> >>
>> >> diff --git a/generic/lib/clcmacro.h b/generic/lib/clcmacro.h
>> >> index 730073a..64b1770 100644
>> >> --- a/generic/lib/clcmacro.h
>> >> +++ b/generic/lib/clcmacro.h
>> >> @@ -1,44 +1,106 @@
>> >>  #define _CLC_UNARY_VECTORIZE(DECLSPEC, RET_TYPE, FUNCTION, ARG1_TYPE) \
>> >>    DECLSPEC RET_TYPE##2 FUNCTION(ARG1_TYPE##2 x) { \
>> >> -    return (RET_TYPE##2)(FUNCTION(x.x), FUNCTION(x.y)); \
>> >> +    return (RET_TYPE##2){FUNCTION(x.s0), FUNCTION(x.s1)}; \
>> >>    } \
>> >>  \
>> >>    DECLSPEC RET_TYPE##3 FUNCTION(ARG1_TYPE##3 x) { \
>> >> -    return (RET_TYPE##3)(FUNCTION(x.x), FUNCTION(x.y), FUNCTION(x.z)); \
>> >> +    return (RET_TYPE##3){FUNCTION(x.s0), FUNCTION(x.s1), FUNCTION(x.s2)}; \
>> >>    } \
>> >>  \
>> >>    DECLSPEC RET_TYPE##4 FUNCTION(ARG1_TYPE##4 x) { \
>> >> -    return (RET_TYPE##4)(FUNCTION(x.lo), FUNCTION(x.hi)); \
>> >> +    return (RET_TYPE##4){ \
>> >> +      FUNCTION(x.s0), \
>> >> +      FUNCTION(x.s1), \
>> >> +      FUNCTION(x.s2), \
>> >> +      FUNCTION(x.s3), \
>> >> +    }; \
>> >>    } \
>> >>  \
>> >>    DECLSPEC RET_TYPE##8 FUNCTION(ARG1_TYPE##8 x) { \
>> >> -    return (RET_TYPE##8)(FUNCTION(x.lo), FUNCTION(x.hi)); \
>> >> +    return (RET_TYPE##8){ \
>> >> +      FUNCTION(x.s0), \
>> >> +      FUNCTION(x.s1), \
>> >> +      FUNCTION(x.s2), \
>> >> +      FUNCTION(x.s3), \
>> >> +      FUNCTION(x.s4), \
>> >> +      FUNCTION(x.s5), \
>> >> +      FUNCTION(x.s6), \
>> >> +      FUNCTION(x.s7), \
>> >> +    }; \
>> >>    } \
>> >>  \
>> >>    DECLSPEC RET_TYPE##16 FUNCTION(ARG1_TYPE##16 x) { \
>> >> -    return (RET_TYPE##16)(FUNCTION(x.lo), FUNCTION(x.hi)); \
>> >> +    return (RET_TYPE##16){ \
>> >> +      FUNCTION(x.s0), \
>> >> +      FUNCTION(x.s1), \
>> >> +      FUNCTION(x.s2), \
>> >> +      FUNCTION(x.s3), \
>> >> +      FUNCTION(x.s4), \
>> >> +      FUNCTION(x.s5), \
>> >> +      FUNCTION(x.s6), \
>> >> +      FUNCTION(x.s7), \
>> >> +      FUNCTION(x.s8), \
>> >> +      FUNCTION(x.s9), \
>> >> +      FUNCTION(x.sa), \
>> >> +      FUNCTION(x.sb), \
>> >> +      FUNCTION(x.sc), \
>> >> +      FUNCTION(x.sd), \
>> >> +      FUNCTION(x.se), \
>> >> +      FUNCTION(x.sf) \
>> >> +    }; \
>> >>    }
>> >>
>> >>  #define _CLC_BINARY_VECTORIZE(DECLSPEC, RET_TYPE, FUNCTION, ARG1_TYPE, ARG2_TYPE) \
>> >>    DECLSPEC RET_TYPE##2 FUNCTION(ARG1_TYPE##2 x, ARG2_TYPE##2 y) { \
>> >> -    return (RET_TYPE##2)(FUNCTION(x.x, y.x), FUNCTION(x.y, y.y)); \
>> >> +    return (RET_TYPE##2){FUNCTION(x.s0, y.s0), FUNCTION(x.s1, y.s1)}; \
>> >>    } \
>> >>  \
>> >>    DECLSPEC RET_TYPE##3 FUNCTION(ARG1_TYPE##3 x, ARG2_TYPE##3 y) { \
>> >> -    return (RET_TYPE##3)(FUNCTION(x.x, y.x), FUNCTION(x.y, y.y), \
>> >> -                         FUNCTION(x.z, y.z)); \
>> >> +    return (RET_TYPE##3){FUNCTION(x.s0, y.s0), FUNCTION(x.s1, y.s1), \
>> >> +                         FUNCTION(x.s2, y.s2)}; \
>> >>    } \
>> >>  \
>> >>    DECLSPEC RET_TYPE##4 FUNCTION(ARG1_TYPE##4 x, ARG2_TYPE##4 y) { \
>> >> -    return (RET_TYPE##4)(FUNCTION(x.lo, y.lo), FUNCTION(x.hi, y.hi)); \
>> >> +    return (RET_TYPE##4){ \
>> >> +      FUNCTION(x.s0, y.s0), \
>> >> +      FUNCTION(x.s1, y.s1), \
>> >> +      FUNCTION(x.s2, y.s2), \
>> >> +      FUNCTION(x.s3, y.s3), \
>> >> +    }; \
>> >>    } \
>> >>  \
>> >>    DECLSPEC RET_TYPE##8 FUNCTION(ARG1_TYPE##8 x, ARG2_TYPE##8 y) { \
>> >> -    return (RET_TYPE##8)(FUNCTION(x.lo, y.lo), FUNCTION(x.hi, y.hi)); \
>> >> +    return (RET_TYPE##8){ \
>> >> +      FUNCTION(x.s0, y.s0), \
>> >> +      FUNCTION(x.s1, y.s1), \
>> >> +      FUNCTION(x.s2, y.s2), \
>> >> +      FUNCTION(x.s3, y.s3), \
>> >> +      FUNCTION(x.s4, y.s4), \
>> >> +      FUNCTION(x.s5, y.s5), \
>> >> +      FUNCTION(x.s6, y.s6), \
>> >> +      FUNCTION(x.s7, y.s7), \
>> >> +    }; \
>> >>    } \
>> >>  \
>> >>    DECLSPEC RET_TYPE##16 FUNCTION(ARG1_TYPE##16 x, ARG2_TYPE##16 y) { \
>> >> -    return (RET_TYPE##16)(FUNCTION(x.lo, y.lo), FUNCTION(x.hi, y.hi)); \
>> >> +    return (RET_TYPE##16){ \
>> >> +      FUNCTION(x.s0, y.s0), \
>> >> +      FUNCTION(x.s1, y.s1), \
>> >> +      FUNCTION(x.s2, y.s2), \
>> >> +      FUNCTION(x.s3, y.s3), \
>> >> +      FUNCTION(x.s4, y.s4), \
>> >> +      FUNCTION(x.s5, y.s5), \
>> >> +      FUNCTION(x.s6, y.s6), \
>> >> +      FUNCTION(x.s7, y.s7), \
>> >> +      FUNCTION(x.s8, y.s8), \
>> >> +      FUNCTION(x.s9, y.s9), \
>> >> +      FUNCTION(x.sa, y.sa), \
>> >> +      FUNCTION(x.sb, y.sb), \
>> >> +      FUNCTION(x.sc, y.sc), \
>> >> +      FUNCTION(x.sd, y.sd), \
>> >> +      FUNCTION(x.se, y.se), \
>> >> +      FUNCTION(x.sf, y.sf) \
>> >> +    }; \
>> >>    }
>> >>
>> >>  #define _CLC_DEFINE_BINARY_BUILTIN(RET_TYPE, FUNCTION, BUILTIN, ARG1_TYPE, ARG2_TYPE) \
>> >> --
>> >> 1.9.1
>> >>
>> >>
>> >> _______________________________________________
>> >> Libclc-dev mailing list
>> >> Libclc-dev at pcc.me.uk
>> >> http://www.pcc.me.uk/cgi-bin/mailman/listinfo/libclc-dev




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