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PowerPC: Fix copysignf optimization macro

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This patch fixes the __copysignf optimized macro meant to internal libm
usage when used with constant value.  Without the explicit cast to
float, if it is used with const double value (for instance, on
s_casinhf.c) double constants will be used and it may lead to precision
issues in some algorithms.

It fixes the following failures on PPC64/POWER7:

Failure: Test: Real part of: cacos_downward (inf + 0 i)
Result:
 is:          1.19209289550781250000e-07   0x1.00000000000000000000p-23
 should be:   0.00000000000000000000e+00   0x0.00000000000000000000p+0
Failure: Test: Real part of: cacos_downward (inf - 0 i)
Result:
 is:          1.19209289550781250000e-07   0x1.00000000000000000000p-23
 should be:   0.00000000000000000000e+00   0x0.00000000000000000000p+0
Failure: Test: Real part of: cacos_downward (inf + 0.5 i)
Result:
 is:          1.19209289550781250000e-07   0x1.00000000000000000000p-23
 should be:   0.00000000000000000000e+00   0x0.00000000000000000000p+0
Failure: Test: Real part of: cacos_downward (inf - 0.5 i)
Result:
 is:          1.19209289550781250000e-07   0x1.00000000000000000000p-23
 should be:   0.00000000000000000000e+00   0x0.00000000000000000000p+0
Failure: Test: Real part of: cacos_towardzero (inf + 0 i)
Result:
 is:          1.19209289550781250000e-07   0x1.00000000000000000000p-23
 should be:   0.00000000000000000000e+00   0x0.00000000000000000000p+0
Failure: Test: Real part of: cacos_towardzero (inf - 0 i)
Result:
 is:          1.19209289550781250000e-07   0x1.00000000000000000000p-23
 should be:   0.00000000000000000000e+00   0x0.00000000000000000000p+0
Failure: Test: Real part of: cacos_towardzero (inf + 0.5 i)
Result:
 is:          1.19209289550781250000e-07   0x1.00000000000000000000p-23
 should be:   0.00000000000000000000e+00   0x0.00000000000000000000p+0
Failure: Test: Real part of: cacos_towardzero (inf - 0.5 i)
Result:
 is:          1.19209289550781250000e-07   0x1.00000000000000000000p-23
 should be:   0.00000000000000000000e+00   0x0.00000000000000000000p+0
This commit is contained in:
Adhemerval Zanella 2014-05-20 16:07:49 -05:00
parent 4406c41c1d
commit e13bccd3de
2 changed files with 8 additions and 1 deletions
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5
ChangeLog
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@ -1,3 +1,8 @@
2014-05-20 Adhemerval Zanella <azanella@linux.vnet.ibm.com>
* sysdeps/powerpc/fpu/math_private.h [__copysignf]: Fix copysign macro
optimization when used with float constants.
2014-05-20 Aurelien Jarno <aurelien@aurel32.net>
[BZ #16915]

4
sysdeps/powerpc/fpu/math_private.h
View File

@ -166,11 +166,13 @@ __ieee754_sqrtf (float __x)
# ifndef __copysignf
# define __copysignf(x, y) \
({ float __z; \
float __x = x; \
float __y = y; \
__asm __volatile ( \
" fcpsgn %0,%1,%2\n" \
" frsp %0,%0\n" \
: "=f" (__z) \
: "f" (y), "f" (x)); \
: "f" (__y), "f" (__x));\
__z; })
# endif