[Bug math/16576] New: PowerPC: glibc attempts to use fsqrt instruction on processors that do not implement it

["adrian at humboldt dot co.uk" <sourceware-bugzilla at sourceware dot org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=16576

            Bug ID: 16576
           Summary: PowerPC: glibc attempts to use fsqrt instruction on
                    processors that do not implement it
           Product: glibc
           Version: unspecified
            Status: NEW
          Severity: normal
          Priority: P2
         Component: math
          Assignee: unassigned at sourceware dot org
          Reporter: adrian at humboldt dot co.uk

In sysdeps/powerpc/fpu/math_private.h, __CPU_HAS_FSQRT is set true on all 64
bit PowerPC processors. Recent 64-bit PowerPC processors (e5500 core) from
Freescale do not implement this instruction, causing any application using
sqrt() to fail.

  28 # if __WORDSIZE == 64 || defined _ARCH_PWR4
  29 #  define __CPU_HAS_FSQRT 1
  30 # else
  31 #  define __CPU_HAS_FSQRT ((GLRO(dl_hwcap) & PPC_FEATURE_64) != 0)
  32 # endif

There is a patch for this in OpenEmbedded, but it provides a compile time fix
which is less useful for Linux distributions. A runtime probe for the existence
of the fsqrt instruction would be of wider use.

http://lists.openembedded.org/pipermail/openembedded-core/2012-September/068696.html

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