[Qemu-devel] [Bug 1761401] [NEW] ARM/Neon: vcvt rounding error

[Qemu-devel] [Bug 1761401] [NEW] ARM/Neon: vcvt rounding error

[Christophe Lyon]

Public bug reported:

Hello,

While using QEMU commit 47d3b60858d90ac8a0cc3a72af7f95c96781125a (March
28, 2018), I've noticed failures in one of the GCC ARM/Neon tests. The
test passes on hardware, and with QEMU-2.11.0, so it looks like a recent
regression.

The test builds a vector of 4 float32 with "125.9" as value, then converts them to 4 uint32_t.
The expected result is 125, but we get 126 instead.

Maybe it's just a matter of default rounding mode?

** Affects: qemu
     Importance: Undecided
         Status: New

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Title:
  ARM/Neon: vcvt rounding error

Status in QEMU:
  New

Bug description:
  Hello,

  While using QEMU commit 47d3b60858d90ac8a0cc3a72af7f95c96781125a
  (March 28, 2018), I've noticed failures in one of the GCC ARM/Neon
  tests. The test passes on hardware, and with QEMU-2.11.0, so it looks
  like a recent regression.

  The test builds a vector of 4 float32 with "125.9" as value, then converts them to 4 uint32_t.
  The expected result is 125, but we get 126 instead.

  Maybe it's just a matter of default rounding mode?

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[Qemu-devel] [Bug 1761401] Re: ARM/Neon: vcvt rounding error

[Peter Maydell]

Hi Christophe -- we think that commit bd49e6027cbc207c, now in master,
should have fixed this bug. Could you retry your testcase with a QEMU
build including that fix?

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https://bugs.launchpad.net/bugs/1761401

Title:
  ARM/Neon: vcvt rounding error

Status in QEMU:
  New

Bug description:
  Hello,

  While using QEMU commit 47d3b60858d90ac8a0cc3a72af7f95c96781125a
  (March 28, 2018), I've noticed failures in one of the GCC ARM/Neon
  tests. The test passes on hardware, and with QEMU-2.11.0, so it looks
  like a recent regression.

  The test builds a vector of 4 float32 with "125.9" as value, then converts them to 4 uint32_t.
  The expected result is 125, but we get 126 instead.

  Maybe it's just a matter of default rounding mode?

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1761401/+subscriptions

[Qemu-devel] [Bug 1761401] Re: ARM/Neon: vcvt rounding error

[Christophe Lyon]

I updated my QEMU git tree such that it includes commit
bd49e6027cbc207c, and the test now passes.

Thanks for the prompt fix!


** Changed in: qemu
       Status: New => Fix Committed

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You received this bug notification because you are a member of qemu-
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https://bugs.launchpad.net/bugs/1761401

Title:
  ARM/Neon: vcvt rounding error

Status in QEMU:
  Fix Committed

Bug description:
  Hello,

  While using QEMU commit 47d3b60858d90ac8a0cc3a72af7f95c96781125a
  (March 28, 2018), I've noticed failures in one of the GCC ARM/Neon
  tests. The test passes on hardware, and with QEMU-2.11.0, so it looks
  like a recent regression.

  The test builds a vector of 4 float32 with "125.9" as value, then converts them to 4 uint32_t.
  The expected result is 125, but we get 126 instead.

  Maybe it's just a matter of default rounding mode?

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1761401/+subscriptions

[Qemu-devel] [Bug 1761401] Re: ARM/Neon: vcvt rounding error

[Thomas Huth]

** Changed in: qemu
       Status: Fix Committed => Fix Released

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devel-ml, which is subscribed to QEMU.
https://bugs.launchpad.net/bugs/1761401

Title:
  ARM/Neon: vcvt rounding error

Status in QEMU:
  Fix Released

Bug description:
  Hello,

  While using QEMU commit 47d3b60858d90ac8a0cc3a72af7f95c96781125a
  (March 28, 2018), I've noticed failures in one of the GCC ARM/Neon
  tests. The test passes on hardware, and with QEMU-2.11.0, so it looks
  like a recent regression.

  The test builds a vector of 4 float32 with "125.9" as value, then converts them to 4 uint32_t.
  The expected result is 125, but we get 126 instead.

  Maybe it's just a matter of default rounding mode?

To manage notifications about this bug go to:
https://bugs.launchpad.net/qemu/+bug/1761401/+subscriptions