ARM/Neon: vcvt rounding error

Bug #1761401 reported by Christophe Lyon
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
QEMU
Fix Released
Undecided
Unassigned

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?

Revision history for this message
Peter Maydell (pmaydell) wrote :

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?

Revision history for this message
Christophe Lyon (christophe-lyon) wrote :

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
Thomas Huth (th-huth)
Changed in qemu:
status: Fix Committed → Fix Released
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