[Qemu-devel] [Bug 1836192] Re: Regressions on arm926 target with some GCC tests

[Peter Maydell]

We didn't spot that armv5 CPUs don't have mvfr0, so now the vfp refactor
is looking at mvfr0 fields to gate feature presence we need to
initialize cpu->isar.mvfr0 specifically to a value that indicates the
right thing even on the armv5 CPUs which don't have a guest-visible
mvfr0. This specifically affects just arm926 and arm1026, which have
accidentally lost short-vector support and double-precision support.

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https://bugs.launchpad.net/bugs/1836192

Title:
  Regressions on arm926 target with some GCC tests

Status in QEMU:
  New

Bug description:
  Hi,

  After trying qemu master:
  commit 474f3938d79ab36b9231c9ad3b5a9314c2aeacde
  Merge: 68d7ff0 14f5d87
  Author: Peter Maydell <email address hidden>
  Date: Fri Jun 21 15:40:50 2019 +0100

  even with the fix for https://bugs.launchpad.net/qemu/+bug/1834496,
  I've noticed several regressions compared to qemu-3.1 when running the GCC 
testsuite, with GCC configured to generate arm10tdmi code by default, and using 
qemu's --cpu arm926.

  I'm attaching a tarball containing one of the GCC tests (binaries),
  needed shared libs, and a short script to run the test.

  This was noticed with GCC master configured with
  --target arm-none-linux-gnueabi
  --with-cpu arm10tdmi
  --with-fpu vfp

  Thanks

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