id = 1788
title = "Floating point rounding fails on mps3-an547 amd cortex-m55 while using LLVM-embedded-toolchain-for-Arm and Picolibic."
state = "closed"
created_at = "2023-07-25T08:31:42.354Z"
closed_at = "2023-08-01T14:41:51.146Z"
labels = ["workflow::Patch available"]
url = "https://gitlab.com/qemu-project/qemu/-/issues/1788"
host-os = "Ubuntu 20.04.5 LTS"
host-arch = "x86_64"
qemu-version = "QEMU emulator version 7.1.0"
guest-os = "N/A"
guest-arch = "mps3-an547 and cortex-m55"
description = """Rounding of long double gives unexpected result. Simple code as example:
```
#include <math.h>
int main(void)
{
  long double value = -8.5L;
  long rounded_value = lrintl(value);
  if( -8 == rounded_value )
  {
    return 0;
  }
  return 1;
}
```"""
reproduce = """1. Checkout project: [LLVM-embedded-toolchain-for-ARM](https://github.com/ARM-software/LLVM-embedded-toolchain-for-Arm)
2. Configure it with option -DLLVM_TOOLCHAIN_LIBRARY_VARIANTS=armv8.1m.main_hard_nofp_mve 
3. Build project
4. Run Picolbic tests with ninja picolibc_armv8.1m.main_hard_nofp_mve-test

As a result long_double test fails with incorrect rounding.
Last qemu version which successfully execute mentioned test is: qemu 7.0.0 downloaded via [qemu-7.0.0](https://download.qemu.org/qemu-7.0.0.tar.bz2). 
Issue is present since qemu version 7.1."""
additional = """As a result long_double test fails with incorrect rounding.
Last qemu version which successfully execute mentioned test is: qemu 7.0.0 downloaded via [qemu-7.0.0](https://download.qemu.org/qemu-7.0.0.tar.bz2). 
Issue is present since qemu version 7.1."""