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

Tom Stellard tom at stellard.net
Wed Jul 30 13:39:40 PDT 2014 

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
> >>
> >>
> >> _______________________________________________
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> >> Libclc-dev at pcc.me.uk
> >> http://www.pcc.me.uk/cgi-bin/mailman/listinfo/libclc-dev

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