[Bug 1892081] Re: Performance improvement when using "QEMU_FLATTEN" with softfloat type conversions

[Thomas Huth]

This is an automated cleanup. This bug report has been moved to QEMU's
new bug tracker on gitlab.com and thus gets marked as 'expired' now.
Please continue with the discussion here:

 https://gitlab.com/qemu-project/qemu/-/issues/134


** Changed in: qemu
       Status: In Progress => Expired

** Changed in: qemu
     Assignee: Richard Henderson (rth) => (unassigned)

** Bug watch added: gitlab.com/qemu-project/qemu/-/issues #134
   https://gitlab.com/qemu-project/qemu/-/issues/134

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https://bugs.launchpad.net/bugs/1892081

Title:
  Performance improvement when using "QEMU_FLATTEN" with softfloat type
  conversions

Status in QEMU:
  Expired

Bug description:
  Attached below is a matrix multiplication program for double data
  types. The program performs the casting operation "(double)rand()"
  when generating random numbers.

  This operation calls the integer to float softfloat conversion
  function "int32_to_float_64".

  Adding the "QEMU_FLATTEN" attribute to the function definition
  decreases the instructions per call of the function by about 63%.

  Attached are before and after performance screenshots from
  KCachegrind.

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