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authorAurelien Jarno <aurelien@aurel32.net>2016-07-31 23:17:47 +0200
committerAurelien Jarno <aurelien@aurel32.net>2016-08-02 02:07:20 +0200
commit33ae5b17cd9bc1bea1e35d9805875b10cb489571 (patch)
treee8173781347efa062491126eae7748c8d043131c /ChangeLog.6
parentfab382315ad3be7c773aaf7ca49c053cf91755fe (diff)
downloadglibc-33ae5b17cd9bc1bea1e35d9805875b10cb489571.tar.gz
sparc: remove ceil, floor, trunc sparc specific implementations
The ceil, floor and trunc functions on sparc do not fully follow the standard and trigger an inexact exception when presented a value which is not an integer. Since glibc 2.24 this causes a few tests to fail, for instance: testing double (without inline functions) Failure: ceil (lit_pi): Exception "Inexact" set Failure: ceil (-lit_pi): Exception "Inexact" set Failure: ceil (min_subnorm_value): Exception "Inexact" set Failure: ceil (min_value): Exception "Inexact" set Failure: ceil (0.1): Exception "Inexact" set Failure: ceil (0.25): Exception "Inexact" set Failure: ceil (0.625): Exception "Inexact" set Failure: ceil (-min_subnorm_value): Exception "Inexact" set Failure: ceil (-min_value): Exception "Inexact" set Failure: ceil (-0.1): Exception "Inexact" set Failure: ceil (-0.25): Exception "Inexact" set Failure: ceil (-0.625): Exception "Inexact" set I tried to fix that by using the same strategy than used on other architectures, that is by saving the FSR register at the beginning and restoring it at the end of the function. When doing so I noticed a comment that this operation might be very costly, so I decided to do some benchmarks. The benchmarks below represent the time required to run each of the function 60 millions of times with different input value. I have done that in the basic V9 code, the VIS2 code, and using the default C implementation of the libc, for both sparc32 and sparc64, on a Niagara T1 based machine and an UltraSparc IIIi. Given I don't have access to a more recent machine), I haven't been able to test the VIS3 version. Also it should be noted that it doesn't make sense to do this benchmark for V8 or earlier as in that case we use the default C implementation. The results are available in the table below, the "+ fix" version correspond to the one saving and restoring the FSR. Niagara T1 / sparc32 -------------------- ceilf ceil floorf floor truncf trunc V9 19.10 22.48 19.10 22.48 16.59 19.27 V9 + fix 19.77 23.34 19.77 23.33 17.27 20.12 VIS2 16.87 19.62 16.87 19.62 VIS2 + fix 17.55 20.47 17.55 20.47 C impl 11.39 13.80 11.40 13.80 10.88 10.84 Niagara T1 / sparc64 -------------------- ceilf ceil floorf floor truncf trunc V9 18.14 22.23 18.14 22.23 15.64 19.02 V9 + fix 18.82 23.08 18.82 23.08 16.32 19.87 VIS2 15.92 19.37 15.92 19.37 VIS2 + fix 16.59 20.22 16.59 20.22 C impl 11.39 13.60 11.39 15.36 10.88 12.65 UltraSparc IIIi / sparc32 ------------------------- ceilf ceil floorf floor truncf trunc V9 4.81 7.09 6.61 11.64 4.91 7.05 V9 + fix 7.20 10.42 7.14 10.54 6.76 9.47 VIS2 4.81 7.03 4.76 7.13 VIS2 + fix 6.76 9.51 6.71 9.63 C impl 3.88 8.62 3.90 9.45 3.57 6.62 UltraSparc IIIi / sparc64 ------------------------- ceilf ceil floorf floor truncf trunc V9 3.48 4.39 3.48 4.41 3.01 3.85 V9 + fix 4.76 5.90 4.76 5.90 4.86 6.26 VIS2 2.95 3.61 2.95 3.61 VIS2 + fix 4.24 5.37 4.30 7.97 C impl 3.63 4.89 3.62 6.38 3.33 4.03 The first thing that should be noted is that the C implementation is always faster on the Niagara T1 based machine. On the UltraSparc IIIi the float version on sparc32 is also faster. Coming back about the fix saving and restoring the FSR, it appears it has a big impact as expected. In that case the C implementation is always faster than the fixed implementations. This patch therefore removes the sparc specific implementations in favor of the generic ones. Changelog: * sysdeps/sparc/sparc32/sparcv9/fpu/multiarch/Makefile [$(subdir) = math] (libm-sysdep_routines): Remove. [$(subdir) = math && $(have-as-vis3) = yes] (libm-sysdep_routines): Remove s_ceilf-vis3, s_ceil-vis3, s_floorf-vis3, s_floor-vis3, s_truncf-vis3, s_trunc-vis3. * sysdeps/sparc/sparc64/fpu/multiarch/Makefile: Likewise. * sysdeps/sparc/sparc32/sparcv9/fpu/multiarch/s_ceil-vis2.S: Delete file. * sysdeps/sparc/sparc32/sparcv9/fpu/multiarch/s_ceil-vis3.S: Likewise. * sysdeps/sparc/sparc32/sparcv9/fpu/multiarch/s_ceil.S: Likewise. * sysdeps/sparc/sparc32/sparcv9/fpu/multiarch/s_ceilf-vis2.S: Likewise. * sysdeps/sparc/sparc32/sparcv9/fpu/multiarch/s_ceilf-vis3.S: Likewise. * sysdeps/sparc/sparc32/sparcv9/fpu/multiarch/s_ceilf.S: Likewise. * sysdeps/sparc/sparc32/sparcv9/fpu/multiarch/s_floor-vis2.S: Likewise. * sysdeps/sparc/sparc32/sparcv9/fpu/multiarch/s_floor-vis3.S: Likewise. * sysdeps/sparc/sparc32/sparcv9/fpu/multiarch/s_floor.S: Likewise. * sysdeps/sparc/sparc32/sparcv9/fpu/multiarch/s_floorf-vis2.S: Likewise. * sysdeps/sparc/sparc32/sparcv9/fpu/multiarch/s_floorf-vis3.S: Likewise. * sysdeps/sparc/sparc32/sparcv9/fpu/multiarch/s_floorf.S: Likewise. * sysdeps/sparc/sparc32/sparcv9/fpu/multiarch/s_trunc-vis3.S: Likewise. * sysdeps/sparc/sparc32/sparcv9/fpu/multiarch/s_trunc.S: Likewise. * sysdeps/sparc/sparc32/sparcv9/fpu/multiarch/s_truncf-vis3.S: Likewise. * sysdeps/sparc/sparc32/sparcv9/fpu/multiarch/s_truncf.S: Likewise. * sysdeps/sparc/sparc32/sparcv9/fpu/s_ceil.S: Likewise. * sysdeps/sparc/sparc32/sparcv9/fpu/s_ceilf.S: Likewise. * sysdeps/sparc/sparc32/sparcv9/fpu/s_floor.S: Likewise. * sysdeps/sparc/sparc32/sparcv9/fpu/s_floorf.S: Likewise. * sysdeps/sparc/sparc32/sparcv9/fpu/s_trunc.S: Likewise. * sysdeps/sparc/sparc32/sparcv9/fpu/s_truncf.S: Likewise. * sysdeps/sparc/sparc64/fpu/multiarch/s_ceil-vis2.S: Likewise. * sysdeps/sparc/sparc64/fpu/multiarch/s_ceil-vis3.S: Likewise. * sysdeps/sparc/sparc64/fpu/multiarch/s_ceil.S: Likewise. * sysdeps/sparc/sparc64/fpu/multiarch/s_ceilf-vis2.S: Likewise. * sysdeps/sparc/sparc64/fpu/multiarch/s_ceilf-vis3.S: Likewise. * sysdeps/sparc/sparc64/fpu/multiarch/s_ceilf.S: Likewise. * sysdeps/sparc/sparc64/fpu/multiarch/s_floor-vis2.S: Likewise. * sysdeps/sparc/sparc64/fpu/multiarch/s_floor-vis3.S: Likewise. * sysdeps/sparc/sparc64/fpu/multiarch/s_floor.S: Likewise. * sysdeps/sparc/sparc64/fpu/multiarch/s_floorf-vis2.S: Likewise. * sysdeps/sparc/sparc64/fpu/multiarch/s_floorf-vis3.S: Likewise. * sysdeps/sparc/sparc64/fpu/multiarch/s_floorf.S: Likewise. * sysdeps/sparc/sparc64/fpu/multiarch/s_trunc-vis3.S: Likewise. * sysdeps/sparc/sparc64/fpu/multiarch/s_trunc.S: Likewise. * sysdeps/sparc/sparc64/fpu/multiarch/s_truncf-vis3.S: Likewise. * sysdeps/sparc/sparc64/fpu/multiarch/s_truncf.S: Likewise. * sysdeps/sparc/sparc64/fpu/s_ceil.S: Likewise. * sysdeps/sparc/sparc64/fpu/s_ceilf.S: Likewise. * sysdeps/sparc/sparc64/fpu/s_floor.S: Likewise. * sysdeps/sparc/sparc64/fpu/s_floorf.S: Likewise. * sysdeps/sparc/sparc64/fpu/s_trunc.S: Likewise. * sysdeps/sparc/sparc64/fpu/s_truncf.S: Likewise.
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