| Summary: | [powerpc] logbl for POWER7 return incorrect results | ||
|---|---|---|---|
| Product: | glibc | Reporter: | Tulio Magno Quites Machado Filho <tuliom> |
| Component: | math | Assignee: | Tulio Magno Quites Machado Filho <tuliom> |
| Status: | RESOLVED FIXED | ||
| Severity: | normal | Flags: | fweimer:
security-
|
| Priority: | P2 | ||
| Version: | 2.25 | ||
| Target Milestone: | 2.26 | ||
| Host: | Target: | powerpc*-linux | |
| Build: | Last reconfirmed: | ||
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- Log -----------------------------------------------------------------
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=c064f6a613844181f411aabb2662384a6aefb69e
commit c064f6a613844181f411aabb2662384a6aefb69e
Author: Tulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com>
Date: Fri Apr 28 19:45:52 2017 -0300
powerpc: Fix logbl on power7 [BZ# 21280]
1. Fix the results for negative subnormals by ignoring the signal when
normalizing the value.
2. Fix the output when the high part is a power of 2 and the low part
is a nonzero number with opposite sign. This fix is based on commit
380bd0fd2418f8988217de950f8b8ff18af0cb2b.
After applying this patch, logbl() tests pass cleanly on POWER >= 7.
Tested on powerpc, powerpc64 and powerpc64le
[BZ #21280]
* sysdeps/powerpc/power7/fpu/s_logbl.c (__logbl): Ignore the
signal of subnormals and adjust the exponent of power of 2 down
when low part has opposite sign.
-----------------------------------------------------------------------
Summary of changes:
ChangeLog | 7 +++++++
sysdeps/powerpc/power7/fpu/s_logbl.c | 24 ++++++++++++++++++------
2 files changed, 25 insertions(+), 6 deletions(-)
Fixed on glibc 2.26 with commit ID c064f6a613844181f411aabb2662384a6aefb69e. This is an automated email from the git hooks/post-receive script. It was
generated because a ref change was pushed to the repository containing
the project "GNU C Library master sources".
The branch, release/2.25/master has been updated
via da3e97f94c80c5d05c0d999e87179aad35f7e975 (commit)
from 0edeadc0d396aa713b808ae50a0058aca5d3837e (commit)
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- Log -----------------------------------------------------------------
https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=da3e97f94c80c5d05c0d999e87179aad35f7e975
commit da3e97f94c80c5d05c0d999e87179aad35f7e975
Author: Tulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com>
Date: Fri Apr 28 19:45:52 2017 -0300
powerpc: Fix logbl on power7 [BZ# 21280]
1. Fix the results for negative subnormals by ignoring the signal when
normalizing the value.
2. Fix the output when the high part is a power of 2 and the low part
is a nonzero number with opposite sign. This fix is based on commit
380bd0fd2418f8988217de950f8b8ff18af0cb2b.
After applying this patch, logbl() tests pass cleanly on POWER >= 7.
Tested on powerpc, powerpc64 and powerpc64le
[BZ #21280]
* sysdeps/powerpc/power7/fpu/s_logbl.c (__logbl): Ignore the
signal of subnormals and adjust the exponent of power of 2 down
when low part has opposite sign.
(cherry picked from commit c064f6a613844181f411aabb2662384a6aefb69e)
-----------------------------------------------------------------------
Summary of changes:
ChangeLog | 7 +++++++
sysdeps/powerpc/power7/fpu/s_logbl.c | 24 ++++++++++++++++++------
2 files changed, 25 insertions(+), 6 deletions(-)
|
The errors affect negative subnormals and values near powers of 2. testing long double (without inline functions) Failure: Test: logb (-min_subnorm_value) Result: is: -1.01100000000000000000000000000000e+03 -0x1.f98000000000000000000000000p+9 should be: -1.07400000000000000000000000000000e+03 -0x1.0c8000000000000000000000000p+10 difference: 6.30000000000000000000000000000000e+01 0x1.f80000000000000000000000000p+5 ulp : 2495687119199326634196634435584.0000 max.ulp : 0.0000 Failure: Test: logb (0x1.ffffffffffffffp1) Result: is: 2.00000000000000000000000000000000e+00 0x1.000000000000000000000000000p+1 should be: 1.00000000000000000000000000000000e+00 0x1.000000000000000000000000000p+0 difference: 1.00000000000000000000000000000000e+00 0x1.000000000000000000000000000p+0 ulp : 40564819207303340847894502572032.0000 max.ulp : 0.0000 Failure: Test: logb (-0x1.ffffffffffffffp1) Result: is: 2.00000000000000000000000000000000e+00 0x1.000000000000000000000000000p+1 should be: 1.00000000000000000000000000000000e+00 0x1.000000000000000000000000000p+0 difference: 1.00000000000000000000000000000000e+00 0x1.000000000000000000000000000p+0 ulp : 40564819207303340847894502572032.0000 max.ulp : 0.0000 Failure: Test: logb_downward (-min_subnorm_value) Result: is: -1.01100000000000000000000000000000e+03 -0x1.f98000000000000000000000000p+9 should be: -1.07400000000000000000000000000000e+03 -0x1.0c8000000000000000000000000p+10 difference: 6.30000000000000000000000000000000e+01 0x1.f80000000000000000000000000p+5 ulp : 2495687119199326634196634435584.0000 max.ulp : 0.0000 Failure: Test: logb_downward (0x1.ffffffffffffffp1) Result: is: 2.00000000000000000000000000000000e+00 0x1.000000000000000000000000000p+1 should be: 1.00000000000000000000000000000000e+00 0x1.000000000000000000000000000p+0 difference: 1.00000000000000000000000000000000e+00 0x1.000000000000000000000000000p+0 ulp : 40564819207303340847894502572032.0000 max.ulp : 0.0000 Failure: Test: logb_downward (-0x1.ffffffffffffffp1) Result: is: 2.00000000000000000000000000000000e+00 0x1.000000000000000000000000000p+1 should be: 1.00000000000000000000000000000000e+00 0x1.000000000000000000000000000p+0 difference: 1.00000000000000000000000000000000e+00 0x1.000000000000000000000000000p+0 ulp : 40564819207303340847894502572032.0000 max.ulp : 0.0000 Failure: Test: logb_towardzero (-min_subnorm_value) Result: is: -1.01100000000000000000000000000000e+03 -0x1.f98000000000000000000000000p+9 should be: -1.07400000000000000000000000000000e+03 -0x1.0c8000000000000000000000000p+10 difference: 6.30000000000000000000000000000000e+01 0x1.f80000000000000000000000000p+5 ulp : 2495687119199326634196634435584.0000 max.ulp : 0.0000 Failure: Test: logb_towardzero (0x1.ffffffffffffffp1) Result: is: 2.00000000000000000000000000000000e+00 0x1.000000000000000000000000000p+1 should be: 1.00000000000000000000000000000000e+00 0x1.000000000000000000000000000p+0 difference: 1.00000000000000000000000000000000e+00 0x1.000000000000000000000000000p+0 ulp : 40564819207303340847894502572032.0000 max.ulp : 0.0000 Failure: Test: logb_towardzero (-0x1.ffffffffffffffp1) Result: is: 2.00000000000000000000000000000000e+00 0x1.000000000000000000000000000p+1 should be: 1.00000000000000000000000000000000e+00 0x1.000000000000000000000000000p+0 difference: 1.00000000000000000000000000000000e+00 0x1.000000000000000000000000000p+0 ulp : 40564819207303340847894502572032.0000 max.ulp : 0.0000 Failure: Test: logb_upward (-min_subnorm_value) Result: is: -1.01100000000000000000000000000000e+03 -0x1.f98000000000000000000000000p+9 should be: -1.07400000000000000000000000000000e+03 -0x1.0c8000000000000000000000000p+10 difference: 6.30000000000000000000000000000000e+01 0x1.f80000000000000000000000000p+5 ulp : 2495687119199326634196634435584.0000 max.ulp : 0.0000 Failure: Test: logb_upward (0x1.ffffffffffffffp1) Result: is: 2.00000000000000000000000000000000e+00 0x1.000000000000000000000000000p+1 should be: 1.00000000000000000000000000000000e+00 0x1.000000000000000000000000000p+0 difference: 1.00000000000000000000000000000000e+00 0x1.000000000000000000000000000p+0 ulp : 40564819207303340847894502572032.0000 max.ulp : 0.0000 Failure: Test: logb_upward (-0x1.ffffffffffffffp1) Result: is: 2.00000000000000000000000000000000e+00 0x1.000000000000000000000000000p+1 should be: 1.00000000000000000000000000000000e+00 0x1.000000000000000000000000000p+0 difference: 1.00000000000000000000000000000000e+00 0x1.000000000000000000000000000p+0 ulp : 40564819207303340847894502572032.0000 max.ulp : 0.0000 Test suite completed: 120 test cases plus 116 tests for exception flags and 116 tests for errno executed. 12 errors occurred.